
Dallol is a volcano hidden beneath a kilometer-thick layer of salt in the Danakil depression in the Afar region, Ethiopia (at ~120 m below sea level). It manifests itself by an incredible variety of colorful springs and fumaroles in an alien landscape of salt, sulphur and other mineral deposits.
The Afar Depression in Ethiopia is such a geologically interesting area.
Oh yeah and it happens to be where a bunch of hominid fossils were found, giving humans a glimpse into our evolutionary history. Australopithecus afarensis, awww yeee.