Makhtesh Ramon is a hollow in Israel's Negev desert forty kilometres long, up to ten kilometres wide and some five hundred metres deep, walled in on every side. It is the largest of the makhteshim, a landform found nowhere on Earth but the Negev and the Sinai, and although it looks like an impact crater no meteorite made it. Drive Route 40 down onto the floor and you can read the rock like an open book: bands of red, purple, yellow and grey up to 200 million years old, with black volcanic hills standing among them. The bare ground here resembles Mars closely enough that space agencies rehearse on it. In October 2021 six volunteers spent a month in a sealed habitat on the crater floor and crossed the rock outside in mock spacesuits.
Water made the hollow instead. A dome of rock was pushed up here, the hard limestone capping it cracked open, and rivers carried the soft sandstone core away after the Arava rift tore the region apart around five million years ago. One spring survives at the lowest point, Ein Saharonim, and it is the only natural water in the whole basin. Nabataean caravans carrying frankincense from Petra towards Gaza depended on it, and the ruins of their roadhouse still stand beside it. At HaMinsara, the Carpentry Shop, a rise of quartzite prisms is squared off so neatly that the stone looks like sawn timber. Nubian ibex graze the rim at first light, and wild asses range the floor below them. Then night comes. In 2017 the reserve was named the first International Dark Sky Park in the Middle East, and on a moonless night the Milky Way stands over the southern wall while the crater underneath stays completely black.