China: The country of thousands of islands!

How many islands are there in China?

According to the latest "Island Statistical Survey Bulletin"

my country has more than

11000

It is truly a “country of ten thousand islands”

(The 2017 Island Survey and Statistical Bulletin does not include data on Hong Kong, Macao and Taiwan; the following figure is a distribution map of China's major islands, please watch it in horizontal mode, drawn by @郑艺/星球研究院)

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These islands

Or lush greenery

(Weizhou Island, Beihai City, Guangxi, photographer @陈肖)

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Or a cluster of houses

(Yuhuan Island, Taizhou City, Zhejiang Province, photographer @傅鼎)

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Or form a beautiful arc

(Please watch horizontally, Qilianyu, Xisha Islands, photographer @李咸良)

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Or thousands of people gathered together, in groups

(Hong Kong and some islands, photographer @吴亦丹)

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11,000 Chinese islands

Like a myriad of worlds on the sea

Show thousands of wonderful

However

Although there are thousands of differences

They all stem from an endless

"Sea and Land War"

01

Attack of the Sea

Three or four billion years ago

Oceans appeared on Earth

The war on sea and land has begun

The ocean tries to swallow the earth

The land was not to be outdone and fought back vigorously.

About 25,000-18,000 years ago

This was the peak of the last glacial period.

Cold climate, widespread glaciers

The sea level was about 140 meters lower than it is now

The continental area reached its peak during this period.

(Diagram of the last glacial maximum and the modern coastline. The former is based on the ancient coastline 19,000 years ago. Map by @郑艺/Planetary Research Institute)

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Afterwards

As global warming and sea level rise

The ocean is coming

Gradually submerging entire continents

Only those lands with higher altitudes

I was lucky enough to escape

Become a survivor in the vast ocean

Continental Island

(Schematic diagram of the main formation principle of continental islands, drawn by @Zheng Borong/Planetary Research Institute)

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In China

There are many continental islands

More than 90% of the total number of islands can be reached

Similar to the mountains that appear in groups on land

Continental islands also tend to cluster into island groups

According to the aggregation form

Distributed in groups as islands

The chain-like distribution is an archipelago

Islands are generally wider

Zhoushan Islands, the largest archipelago in my country

It consists of 1814 islands.

Accounting for 16% of the total number of islands in China

These include the Qiqiu Islands and the Zhongjieshan Islands.

Ma'an Islands and other islands

(Schematic diagram of Zhoushan Islands, drawn by @Zheng Yi/Planetary Research Institute)

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also

Continental islands are generally larger in area

For example, the two largest islands in my country

Taiwan Island and Hainan Island

All belong to continental islands

Features: Large quantity and large area

Make the landscape on the mainland island more colorful

For example, the huge mountains towering over the island

(Qingshui Cliff, located on the east side of the Central Mountain Range in Taiwan Province, photographer @小虎牙-赵祎)

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Like the granite that covers the earth's surface

(Haitan Island, Fuzhou City, Fujian Province, photographer @陈小羊)

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Or

Vast meadows and blue lakes

(Dayu Mountain is located in the southeastern waters of Fuding City, Fujian Province, photographer @赵高翔)

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However

The ocean does not intend to let these "survivors" go

It regards the mainland island as a "thorn in the eye" and "thorn in the flesh"

Determined to wear it out

Under the impact of the waves

Coastal rocks gradually form groove-shaped depressions

Sea Caves

For example, Huaaoshan Island in Ningbo, Zhejiang

Columnar joints formed by volcanic activity

Sea caves formed by waves

Appearing in the same frame

(Sea erosion caves on Huaaoshan Island. The island is full of columnar joints of volcanic eruptive rocks, with diverse shapes and abundant numbers. It is known as the "First Stone Forest on the Sea". Photographer: @石耀臣)

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As sea caves are enlarged by waves

The top rock collapsed, forming a steep wall

Sea cliff

The waves continue to erode

Sea caves continue to go deeper

Its bottom was gradually leveled by the waves.

A sea erosion platform will be formed

If you encounter more prominent coastal rocks

The sea caves on both sides are eroded and connected to each other.

The remaining rocks became a "bridge"

Also known as the Sea Arch Bridge

For example, the Jinshitan Beach in Dalian, Liaoning

The rock is penetrated to form a "bridge"

It also makes the rocks on one side more eye-catching.

It's like a dinosaur sticking its head out into the sea

It is called "Dinosaur Exploring the Sea"

(Dinosaurs exploring the sea, just for illustration, photographer @梁炳全)

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If the sea erosion arch bridge collapses

Leaving behind a rock column separated from the mainland

Standing alone in the sea

Sea stacks

For example, Gaoshan Island in Yantai, Shandong

Two sea stacks at the front

Like a sail standing in the sea

Shifan Reef

(The two sea stacks on the right side of the picture are Shifan Reef, also known as "Two Masts"; the frontmost sea stack has been eroded through, becoming a unique sea arch bridge, photographer @徐树春)

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If the separated rock mass is large

Smaller islands will also be formed

For example, Bangchui Island in Dalian

The area is only about 0.05 square kilometers

(Dalian Bangchuidao, the island formed by this cause is called an erosion island, photographer @何健)

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In the face of the constant waves

The coastline of the continental island is constantly retreating

Leaving behind a variety of sea erosion landforms

Become a unique landscape

(Sketch of sea erosion landforms, drawn by @王天怡&王申雯/Planetary Research Institute)

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Although the erosion process of the ocean is slower

But as time goes by

Even the hardest rock can't stop

Continental Island

Will eventually disappear into the ocean

(Basalt columns are eroded by waves, and fragments fall into the sea, located in Penghu Islands, Taiwan Province, photographer @吴贤宾)

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The ocean is coming with great force.

The land will never sit still and wait for death

It has accumulated strength

Prepare to strike back

02

Land strikes back

The “sea-land war” in coastal areas is the most intense

The ocean erodes the land, and the land returns its color

Rivers roll in from the land

Carrying a lot of sand and mud to the sea

Taking on the Ocean

The river and the sea are clearly separated, and it is located near the mouth of the Yellow River in Dongying City, Shandong Province. The Yellow River carries silt to the sea, and due to the high density of seawater, the water of the Yellow River is "supported" to the upper layer, thus forming a landscape with distinct yellow river water and blue sea water.

When rivers flow into the sea

The water surface widens at the river mouth and the flow slows down

The sediment was deposited to form land

Alluvial islands are formed in the estuary

(Schematic diagram of the formation of estuary alluvial islands, drawn by @Zheng Borong/Planetary Research Institute)

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The strength of rivers and oceans

Will determine the fate of the estuarine alluvial island

The river mouth where the river is stronger

The Yellow River Estuary

Its estuary alluvial islands are very unstable

It is easy to be cut into new sand islands by floods during the flood season

Or because of the rapid accumulation of sediment

This causes the alluvial island to merge into the delta.

(Please watch in horizontal screen, the mouth of the Yellow River, located in Dongying, Shandong, photographer @董保华)

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Estuaries with strong ocean forces

Qiantang River Estuary

The silt will soon be dispersed by the strong tide.

Difficult to form alluvial islands

(Qiantang River Tide, Photographer @陈中秋)

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The river is as powerful as the ocean.

The sediment can be in a relatively stable state

Gradually accumulated to form large alluvial islands

Yangtze River Estuary

Although the sediment transport volume is far less than that of the Yellow River

But it has formed the largest estuarine alluvial island in China.

Chongming Island

(Please watch in horizontal mode, passing the Shanghai Yangtze River Bridge to Chongming Island. Chongming Island is the third largest island in my country, second only to Taiwan Island and Hainan Island. Photographer @老J)

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This type of stable and large alluvial island

Generally flat terrain and fertile soil

Chongming Island has thousands of acres of fertile land

(Please watch in horizontal mode, Chongming Island rice fields, photographer @大徐)

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and dense forests

(Metasequoia in autumn, located in Chongming Dongping National Forest Park, photographer @丁俊逸)

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now

Due to the continuous sedimentation of

Chongming Island is still growing

Its eastern beach is advancing 350 meters toward the sea every year.

Nearly 10,000 acres of land was reclaimed

The northern part of the country has seen an increase in siltation.

It also made the entire Chongming Island gradually move northward.

Maybe in the not too distant future

We will witness the historic moment of Chongming Island's integration into the mainland

(Sketch of the change in the location of Chongming Island, drawn by @Zheng Yi/Planetary Research Institute)

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Except the estuary

Most of the silt also washed into the sea

Under the influence of waves and currents

The sediment in the ocean accumulates into land

(Fishbone Sandbar, located on Dongshan Island, Zhangzhou, Fujian, photographer @徐昌宇)

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first

The ocean current flows along the coast forming longshore drift

The sediment drifts along the coast.

Deposits on the coast near river mouths

(Sketch of the formation of sand spits, bay mouth sandbars and island-linked sandbanks, drawn by @王申雯/Planetary Research Institute)

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At the turning point of the coast

The water flow rate slows down and the sediment settles quickly

Forming a long strip of sand deposits extending toward the ocean

Sand Spit

(Xiangbi Bay, located on Haitan Island, Fuzhou, Fujian, photographer @陈小羊)

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The sand spit continues to extend

Will eventually connect to the land

Formation of sandbar at the mouth of the bay

(A sand spit that is about to form a sandbar at the mouth of the bay, with a lagoon that is not completely closed behind it, located in Houhai, Sanya, Hainan. Photographer: @韩阳)

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Then the waves hit

Or cut off the sand spit and bay mouth sand bar

Or re-roll, transport and accumulate the seabed mud

In either case

Will form a long and narrow sand island

They protect the continent like a barrier

Hence they are called barrier islands

(Barrier Island, located in Caofeidian District, Tangshan, Hebei. To facilitate readers' identification, the color of the picture has been enhanced. The yellow one is the barrier island. Photographer @陈剑峰)

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also

To the offshore islands

Silt can also help

Affected by longshore currents

The sand accumulates between the island and the land.

Forming sandbars

These islands connected to the mainland

Lulian Island

Sandbanks can also exist between two islands.

Connected islands

While increasing the area

It also increases the power to fight against the ocean

(Dazhou Island, Wanning, Hainan, photographer @蔡晶)

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In addition to coastal currents

Tidal currents

It also affects the movement of sediment in the sea.

Formation of tidal sand ridges controlled by tidal currents

There are rare tidal sand ridges along the coast of Jiangsu

Roughly centered at Jianggang along the Jiangsu coast

Radial currents act here

Transform the submerged ancient estuary into a group of radial sand ridges

Therefore, it is named the South Yellow Sea Radial Sand Ridge Group

(Diagram of the radiation sand ridges and tidal currents in the South Yellow Sea, drawn by @Zheng Yi/Planetary Research Institute)

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Unlike most underwater sand ridges

The radial sand ridges in the South Yellow Sea are mainly distributed in the intertidal zone.

And a few sand ridges have reached sufficient height

Become a sand island

This sand ridge group has a total area of ​​22,470 square kilometers.

While creating beautiful scenery between the ebb and flow of the tide

Large wetlands have also been formed

The vegetation is lush

It is an "oil painting" of the earth

(Colorful grass beaches in the radial sand ridges of the South Yellow Sea, located in the Yancheng Rare Bird National Nature Reserve in Jiangsu Province, photographer @孙华金)

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Animal life

A paradise for migratory birds

(The Yellow [Bohai] Sea Bird Habitat in China is China's first marine world natural heritage site, photographer @孙华金)

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It is also China's "Hometown of Elk"

(Running elk, yellow sand ridges and blue water troughs, taken in Dafeng District, Yancheng, Jiangsu Province, photographer @孙华金)

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So far

Silt gathers to form continents

Creating land in and around estuaries

Successfully launched a counterattack on behalf of the land

However

In the face of the overwhelming force of the ocean swallowing the earth

This counterattack is slightly insufficient

Land never gives up easily

It burned its boats and went deep into the ocean

Trying to survive from the bottom of the sea

03

Undersea Force

Deep seabed

It's the death zone on land.

The emergence of magma

Helping the land to come back to life

Hot magma

Erupting from the rupture on the seafloor

Cooling and stratification, gradually accumulating into mountains

(Contemporary underwater volcanic eruption scene, image source @NOAA)

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When some of them emerged from the sea

Forming new land in the sea

Volcano Island

Some volcanic islands are formed at the edges of plates.

Heavier oceanic plates are subducted deeper into the Earth's interior

Magma erupts from the ocean floor through cracks

Then it solidified and accumulated, revealing the sea surface

(Schematic diagram of the formation of volcanic islands at the edge of plates, drawn by @Zheng Borong/Planetary Research Institute)

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These volcanic islands are often arranged in an arc shape.

Known as an island arc

For example, many islands near Taiwan Island in my country

Lanyu, Green Island, Guishan Island, etc.

(Distribution diagram of Taiwan Island and the two major island arcs in East Asia, drawn by @Zheng Yi/Planet Research Institute)

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But more volcanoes are born inside the plates.

It never emerged from the sea

Becoming a "volcanic remnant"

But a magical creature

Bringing "life" to the "volcanic remains"

They produce reefs on it

Create land in the ocean instead of magma

This organism is a reef-building coral

(Coral, taken in Anilao, Philippines, for illustration only, photographer @刘晨)

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Reef-building corals often live in symbiosis with zooxanthellae

This photosynthetic symbiotic algae

Can increase the rate at which reef-building corals secrete calcium carbonate skeletons

Thus, in the replacement of old and new generations of corals,

Forming coral reefs

(Coral reef, for illustration only; zooxanthellae not only provide energy for reef-building corals through photosynthesis, but also make corals colorful. Photographer @商睿)

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The growth environment of reef-building corals is relatively harsh

The optimal seawater salinity is 3.4%-3.5%

The best water temperature is 25-29℃

And plenty of sunshine

This makes reef-building corals usually appear

Clear, warm shallow tropical waters

(Distribution diagram of coral reefs in China, drawn by @Zheng Yi/Planet Research Institute)

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Although the central part of the South my country Sea is a large deep-water area

But the volcano

It happens to provide a shallow sea environment for corals

Reef-building corals will be at the right depth

Attached to hard volcanic rock

To get more sunlight

They grow upwards

Gradually approaching the sea

The waves want to break these rocks

But it also allows reef fragments to accumulate on the coral reef

And gradually emerged from the sea, forming land in the sea

Ocean's attack helps corals

Completed the feat of creating land in the sea

At this time, the coral reef is like a skirt around the island

It is figuratively called a fringing reef

Because of its surrounding state

Also known as fringing reef

(Fenjiezhou Island in Hainan. The light blue ring around the island underwater near the shore is the location of the fringing reefs [fringe reefs]. Fenjiezhou Island is a continental island, not a volcanic island. This is just for illustration. Photographer @沈龙泉)

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However, sea level rise or seabed subsidence

It will cause the volcano to sink relatively and the coral reefs to sink.

But the desire to chase the sun makes the reef-building corals strive to grow upwards.

Gradually forming coral reefs at a certain distance from the coast

Like a wall surrounding a castle in the middle

Barrier Reef

The volcano continued to descend until it was completely submerged.

The corals are still struggling to grow

Only a circular coral reef remains on the sea surface.

Called an atoll

So far

Coral completely relays magma

Successfully created land in the sea

Leading the land back to life

(Schematic diagram of the evolution of coral atolls, drawn by @Zheng Borong/Planetary Research Institute)

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that's all

Continental islands, estuarine alluvial islands, volcanic islands, coral reefs

The "Sea and Land War"

11,000 islands came into being

The “Land of Ten Thousand Islands” was born

04

Humans and Islands

Thousands of Islands

Although both originated from the "naval and land wars"

But their diverse and widely distributed

It has multiple meanings for humans

They are the sustenance of faith

(Nanhai Guanyin Statue, located in Putuo Mountain, Zhoushan, Zhejiang)

They are proof of history

(The Beiyang Navy Loyal Soul Monument is located on Liugong Island, Weihai, Shandong Province. Photographer: @Jianwangdexingshejie)

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They are strong defense bases.

(Kaishan Island is located in Lianyungang, Jiangsu. Wang Jicai and his wife Wang Shihua have been guarding the island for the country for more than 30 years since 1986; the movie "The Island Guardians" is based on their real deeds)

They manage maritime territories.

Supporting place

(Yongxing Island, the seat of the Sansha Municipal Government of Hainan Province. The island is fully functional and has an airport)

They also obtain marine resources.

Important base

Fish, shrimp, crab, shellfish

Let's get busy gathering and fishing

(Fishing raft, located on Hailing Island, Yangjiang, Guangdong, photographer @姚朝辉)

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Rich in plankton

It also attracted us to establish an offshore ranch

(Oyster farming row and Longmen 72 Jing, located in Maoweihai, Qinzhou Bay, Guangxi, photographer @陈琳)

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To transport various resources

We develop shipping

Islands become our guiding lights at sea

(Please watch in horizontal screen, Flower and Bird Lighthouse, located on Flower and Bird Island in Shengsi Islands, Zhoushan, Zhejiang, photographer @赵高翔)

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We build ports

Islands are often our ideal choice

(Shanghai Yangshan Port, located on the rugged islands outside the mouth of Hangzhou Bay, is the world's largest intelligent container terminal. Photographer @大徐)

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We even transformed the entire island

For repairing and building ships

(Dachan Island [left] and Mazhou Island [right] in Shenzhen, Guangdong. The entire Mazhou Island has been transformed into a shipyard. Photographer @吴亦丹)

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We also build dams and sea bridges

Connecting the mainland to the islands

(Fujian Pingtan Strait Highway-Railway Bridge [under construction], this bridge has been completed. Photographer @陈剑峰)

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And create artificial islands

Used as the interface for cross-sea bridges and undersea tunnels

(Hong Kong-Zhuhai-Macao Bridge West Artificial Island Port, photographer @黄昆震)

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but

Rapid global warming is changing ocean conditions

first

Sea level rise too fast

Low altitude islands

Will face the fate of being submerged

(Please watch in horizontal mode. Changxing Island is located at the mouth of the Yangtze River. It is an estuarine alluvial island with a low altitude. If the sea level rises rapidly, the risk of being submerged is very high. Photographer @傅鼎)

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Secondly

Rising sea temperatures

This will cause reef-building corals to lose their symbiotic algae

Then it loses its luster and turns white.

Until death

therefore

We need to change our energy structure

Vigorously develop green energy

(Wind power and fishermen, near Haiwangjiu Island, Liaoning Province, photographer @No One Xiaodong)

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We need to plant trees, save energy and reduce emissions

To reduce greenhouse gas emissions

(Please watch in horizontal screen, artificial mangrove forest, located in Shuidong Town, Dianbai, Maoming City, Guangdong Province, photographer @张向良)

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Protecting the ecology

Protecting the Ocean

Only then can 11,000 Chinese islands

Continue to show their thousands of beauties

This article was created by

Written by: Shanyuelou

Editor: Director

Image: Pan Chenxia

Map: Zhengyi

Design: Wang Shenwen & Zheng Borong & Wang Tianyi

Reviewer: Yunwukongcheng&Silent&Chen Zhihao

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[5] China Islands Compilation Committee. China Islands. Zhejiang Volume. Volume 2, Southern Zhoushan Islands[M]. Ocean Press, 2014.

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[14] Wang Ying (ed.). Environment and Resources of the Radiating Sand Ridges in the South Yellow Sea. Beijing: Ocean Press, 2014.10.

[15] Wang Peng, ed. Hainan Corals. Beijing: Ocean Press, January 2017.

[16] Zhou Congzhi et al. Development and Utilization of Freshwater Lenses in Coral Islands and Reefs. Chongqing: Chongqing University Press, August 2017.

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Source: Planet Research Institute

A group of National Geographic fans, focusing on exploring the extreme world