Desert Oases
Water in an impossible place, and a settlement organised entirely around it: palm groves, underground channels, mud-brick walls and a temperature swing of thirty degrees between noon and dawn. Arrive late in the day and stay for the night sky.
Every town in this collection is an answer to the same question: where does the water come from, and how do you keep it from evaporating before you use it?
The answers are the most impressive engineering in the atlas, and almost none of it is visible. Turpan sits 154 metres below sea level in one of the hottest places in China and grows grapes, because the karez — thousands of kilometres of hand-dug tunnel — bring snowmelt down from the Tian Shan underground, where it cannot evaporate. Yazd does the same with qanats and adds badgirs, wind towers that catch any breeze and drive it down over water to cool the rooms below. Siwa has hundreds of springs in a depression eighteen metres below sea level, and grew citrus and olives on them for two and a half thousand years.
The others are answers of a different kind. San Pedro sits in the driest desert on earth, so dry that it holds the world's largest radio telescope array because there is almost no water vapour in the air to interfere. Nazca's lines survive precisely because nothing falls on them. AlUla and Dunhuang existed to water caravans, and their monuments are what the traffic paid for.
None of these places is a landscape with a town in it. Each is a piece of hydraulic reasoning that happens to be inhabited, and the reasoning is usually older than anything you can see.