Sossusvlei is a clay pan deep in the Namib Desert of Namibia where the Tsauchab River dies in the sand, walled in by rust-red dunes more than 300 metres tall, among the highest on Earth, climbed at dawn for the view down onto a field of trees that died centuries ago. The sand is coated in iron, and its red changes with the light: apricot at dawn, orange at midday, deep red in the last hour. Big Daddy is the one to climb, a knife-edge spine of soft sand that gives way with every step, so that the ascent is slow, sinking work, and the top gives the widest view in the dune sea, with the white pan of Deadvlei straight below. Then you run down the face, sand sliding away underfoot, and walk out onto the pan.
Deadvlei is a slab of cracked white clay, and rooted in it stand the black, sun-scorched skeletons of camel-thorn trees that died some 600 to 700 years ago, when the dunes cut off the river; the air is so dry that they never rotted, and they stand as they died, against red sand and a blue sky. Almost no rain falls here, yet the desert is alive, because most of its water arrives as fog rolling in off the cold Atlantic and drifting far inland over the dunes. The sand is written over with tracks, beetles that drink the fog, lizards, a passing oryx, and tough plants hold on in the hollows. In rare wet years the river breaks through and floods Sossusvlei itself into a shallow mirror ringed by the dunes; Deadvlei, blocked for centuries, stays dry. Balloons go up at first light over the grass flats beside the dune sea, where the ground is pockmarked with thousands of bare circles, four to ten metres across, that nobody has fully explained. At night, under one of the darkest skies on Earth, the Milky Way's core stands over the dunes in winter. The trees at Deadvlei have been dead for six centuries, and they are still standing where the river left them.