Photo by Edilson V. Benvenutti
On the border between Chile and Bolivia lies the Ollague Volcano, surrounded by a fantastic landscape of salt pans and other Volcanos. Before leaving inform the police about your trip.
The walk starts in the small village of Ollague (3600 m, very basic supplies and facilities).
You can make the peak easily in two days with a camp in a stone hut (no roof) around 4500 m (I called it "The Ritz" to honour Shackleton and his men).
It's a straight forward walk on an old mining road, near the peak you will find some volcanic activity.
For bikes it can't be recommended due to the very bad conditions of the track.
Thanks to Michael Borsdorf for this description.