Jiaohe: The Ancient City Carved into Earth in Western China

This city grew downward. Most of it was never built.

It was carved into the ground. This is Jiaohe in the desert of Western China on an island of earth about a mile long.

Two rivers split around it and cliffs about a hundred feet high drop on every side.

There are no city walls. The cliffs were the wall.

Builders dug down into the earth and left walls standing.

Streets, houses, and temples took shape from the same earth.

Around seven thousand people once lived up here.

The whole city is made of earth. Parts of it are about two thousand years old, and they still stand because it almost never rains here.

This island had hundreds of deep wells with rivers flowing below.

Then, after more than a thousand years, Jiaohe emptied and never filled again.

Some blame a Mongol war. Others blame the rivers running low or conflicts between faiths.

The sources still disagree.

What emptied this city? A war or the desert itself?