What it is
A canyon about 160 km long and up to 550 m deep, cut by a river that is a chain of still pools for most of the year. The main viewpoints are at Hobas on the eastern rim. Ai-Ais, with hot springs, sits at the southern end.
Why go
The rim views take an hour and are why most people stop. The hike is why the others come: roughly 85 km along the canyon floor over four to five days, carrying everything, with no exit once you have started down.
When to go
Rim viewing works any month and is best at sunrise or in the last hour of light. The hike runs only in the cool season, roughly May to mid-September, and needs a permit, a group of at least three and a recent doctor's certificate. Summer floor temperatures pass 45C and the trail is closed.
Most people stay 1-2 nights.