For a close encounter with the Auvergne's geological history, walk the scorched soil at this mined volcanic site off the D941. In summer, at weekends and during school holidays, a motorised "train" chugs for 3km through the scarlet dust, weaving past boulders flung out of the belly of this ancient volcano. Year-round the site is visitable on guided walks. Lemptégy's geological forces are further explained in a short "dynamic 3D" film (available in multiple languages) – expect bumps and jolts. Allow 2¾ hours.
The site opens sporadically in November, February and March; check details on the website.
