Are the colours of the Rainbow Mountains real?

Yes. The colours are natural, coming from layers of sediment with different minerals, especially iron compounds. Many photographs online are enhanced, though, so in person the colours are often softer.

What does danxia mean?

Danxia is a Chinese term, often translated as rosy clouds, for landscapes carved from red sandstone and conglomerate. It is named after Mount Danxia in Guangdong Province.

Is Zhangye Danxia a World Heritage Site?

Not as part of the China Danxia World Heritage listing of 2010, which covers sites in southern China. Zhangye is, however, a UNESCO Global Geopark.

When is the best time to see the colours?

Around sunrise and sunset, when low sunlight warms the colours, and after rain, when damp rock looks more vivid. Summer and early autumn are the main visiting seasons.

Can I explore Zhangye Danxia in the app?

Yes. You can land among hills modelled on Zhangye Danxia and explore their colourful striped ridges and valleys in interactive 3D.

Rainbow-striped hills painted by millions of years of sediment, iron and desert weather

Zhangye Danxia

3D landscape · Zhangye National Geopark, Gansu, China

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In the north-western Chinese province of Gansu, on the edge of the Qilian Mountains, rolling hills are striped like a layer cake in shades of red, orange, yellow, cream and grey-green. These are the Zhangye Danxia landforms, often called the Rainbow Mountains, protected within the Zhangye National Geopark near the city of Zhangye. In this app you can land among hills modelled on Zhangye Danxia and explore their colourful ridges and valleys in interactive 3D.

The colours are entirely natural. They are the edges of rock layers, each with its own minerals, that were laid down long ago, then tilted and folded by the slow collision of India with Asia and finally carved by wind, rain and frost in an arid climate. Zhangye also lies in the Hexi Corridor, a narrow passage that was once part of the Silk Road, so the landscape sits within one of the great crossroads of history.

Key facts

Location: Gansu Province, ChinaIn Linze and Sunan counties near Zhangye, at the foot of the Qilian Mountains
Popular name: Rainbow MountainsAlso known as the Colourful Danxia or Rainbow Hills
Rock types: Red sandstone, conglomerate, siltstone, mudstoneSediments laid down by rivers and lakes
Main age: Largely CretaceousRoughly 145–66 million years old; some layers may be older or younger
Mountain building: India–Asia collisionBegan roughly 50 million years ago and lifted the Tibetan Plateau and Qilian Mountains
Climate: AridTypically only a couple of hundred millimetres of rain a year or less
Historic route: Hexi CorridorA key stretch of the Silk Road between China's heartland and Central Asia
UNESCO status: UNESCO Global GeoparkZhangye joined the Global Geoparks Network in 2019
Best light: Sunrise, sunset and after rainLow sun and damp rock make the colours look richer

What danxia landforms are

Danxia is a Chinese term for landscapes carved from thick layers of red continental sedimentary rock, mostly sandstone and conglomerate deposited by rivers and in lakes rather than in the sea. The name comes from Mount Danxia in Guangdong Province in southern China and is often translated as rosy clouds. Classic danxia scenery includes steep red cliffs, towers, pillars, gorges, natural arches and isolated peaks shaped by erosion along cracks in the rock.

Zhangye shows two kinds of landscape. Around Binggou, erosion has carved red rock into cliffs, towers and castle-like forms closer to classic danxia. The more famous rainbow area consists of rounded, striped hills of softer, finer-grained rock, sometimes described separately as colourful hills. Some geologists debate whether these hills should strictly be called danxia, but the name Zhangye Danxia is now widely used for the whole area.

Why the hills are striped

The stripes began as layers of sediment. Over millions of years, mainly during the Cretaceous period, rivers, lakes and floodplains in a basin here laid down sand, silt and mud, one layer on top of another. The climate and water conditions changed over time, so each layer received a slightly different mix of minerals. Buried and compacted, the layers hardened into sandstone, siltstone, mudstone and conglomerate.

Much of the colour comes from iron. Where iron in the sediment was strongly oxidised, it formed minerals such as hematite, giving deep reds. Other iron oxides and hydroxides give yellows and oranges. Where conditions were low in oxygen, for example in waterlogged sediment, iron stayed in a reduced form and the rock tends towards grey, green or blue-grey. Other minerals, such as clays and gypsum, can add paler white and cream bands.

Tilted, folded and lifted

The layers were originally flat. As the Indian plate pushed into Asia, the crust far to the north was squeezed, building the Qilian Mountains. The rocks at Zhangye were tilted, folded and uplifted, so that erosion now cuts across the layers and exposes their edges as stripes running over the hills.

The colours, the light and the dry climate

Zhangye's colours can look surprisingly different from hour to hour. In harsh midday sun the hills can appear washed out, but at sunrise and sunset the low, warm light deepens the reds and oranges and picks out ridges with long shadows. After rain, damp rock looks darker and more saturated, rather as a pebble looks brighter when wet. Many photographs of the area are also strongly colour-enhanced, so the real landscape is often softer in tone than images online suggest.

The arid climate is a big reason the colours can be seen at all. The Hexi Corridor lies far from the ocean and in the rain shadow of high mountains, so rainfall is low, summers are hot and winters are cold and dry. With so little rain, very little soil or vegetation forms on the slopes to hide the rock. The occasional heavy downpour, frost and wind slowly wear the soft rock into ridges, gullies and rounded hills.

The Silk Road and the Hexi Corridor

Zhangye sits in the Hexi Corridor, a long, narrow strip of land in Gansu between the Qilian Mountains to the south and the deserts and highlands to the north. Fed by meltwater from the mountains, its oases offered a natural route between the Chinese heartland and Central Asia. For more than two thousand years, traders, soldiers, monks and envoys travelled this way along the network of routes now known as the Silk Road.

Zhangye, historically known as Ganzhou, was an important oasis town and garrison on the route. Buddhism spread along the corridor, and Zhangye's Great Buddha Temple is known for a very large reclining Buddha statue. According to Marco Polo's account of his travels, he spent around a year in the city in the thirteenth century. Further west along the corridor lie Jiayuguan, at the western end of the Ming Great Wall, and Dunhuang, with its famous Mogao Caves.

UNESCO and protection

In 2010, UNESCO inscribed China Danxia on the World Heritage List as a single property made up of several separate sites in southern and south-eastern China, chosen to represent the range of danxia landforms in humid subtropical settings. Zhangye is not one of the sites in that World Heritage listing, which is sometimes confused in travel writing.

Zhangye has its own international recognition. The area is protected as the Zhangye National Geopark, and Zhangye became a UNESCO Global Geopark in 2019. Global Geoparks are areas with geological heritage of international significance that are managed for protection, education and sustainable development. This is a different programme from World Heritage, though both are run under UNESCO.

Visiting and protecting the fragile surface

Visitors to the main scenic area travel between viewpoints on shuttle buses and explore on foot along boardwalks, stairways and viewing platforms built on top of the ridges. These give sweeping views across the striped hills, especially popular at sunrise and sunset. Summer and early autumn are the busiest seasons, and the high, dry climate means strong sun, so water and sun protection are essential.

The striped surface is far more delicate than it looks. The soft, crumbly rock is easily marked, and a single footprint can scar the slope for years because there is so little rain or plant growth to heal it. Walking off the boardwalks is forbidden, and there have been widely reported cases of tourists damaging the hills by climbing over barriers. Staying on marked paths helps keep the colours intact for future visitors.

Surprising facts about Zhangye Danxia

The rainbow stripes are the edges of rock layers that were tilted and folded by the collision of India with Asia.
Red bands in the hills owe their colour to oxidised iron, essentially a form of rust.
The colours look richest after rain and in the low light of sunrise and sunset.
Many famous photographs of the Rainbow Mountains have been strongly colour-enhanced.
Zhangye is a UNESCO Global Geopark, but it is not part of the China Danxia World Heritage listing.
A single footprint on the soft slopes can remain visible for years in the dry climate.

Frequently asked questions

Are the colours of the Rainbow Mountains real?: Yes. The colours are natural, coming from layers of sediment with different minerals, especially iron compounds. Many photographs online are enhanced, though, so in person the colours are often softer.
What does danxia mean?: Danxia is a Chinese term, often translated as rosy clouds, for landscapes carved from red sandstone and conglomerate. It is named after Mount Danxia in Guangdong Province.
Is Zhangye Danxia a World Heritage Site?: Not as part of the China Danxia World Heritage listing of 2010, which covers sites in southern China. Zhangye is, however, a UNESCO Global Geopark.
When is the best time to see the colours?: Around sunrise and sunset, when low sunlight warms the colours, and after rain, when damp rock looks more vivid. Summer and early autumn are the main visiting seasons.
Can I explore Zhangye Danxia in the app?: Yes. You can land among hills modelled on Zhangye Danxia and explore their colourful striped ridges and valleys in interactive 3D.

Keep exploring

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

Sources