I took a car and guide from Baku to the famed Mud Volcanoes of Qobustan (Gobustan).
Despite their splendid name, they are actually only about 6 feet tall. They gently burp forth mud and methane from deep mud reservoirs. Sporadic trickles of mud run down from the small cones. If they are lucky the craters occasionally manage to spit up a baseball size lump of mud a foot or so. It all seems very small scale, but remember this is a geologic process that has been running gently for millennia and, yes, the big hilly area the volcanoes stand on has probably been slowly built up from the burped mud.
They are a little goofy, but good fun, and well worth a short visit.