Doupovské hory

The remains of a huge Tertiary volcano, mostly locked inside a military area — walkable only on its rim, which keeps it the wildest corner of the northwest.

You will walk the rim, and only the rim: the Hradiště military training area has held the interior since the 1950s, its villages razed, and the massif — the eroded body of one enormous Tertiary volcano — remains the country’s largest blank spot. Accept that before planning, because it is also the reward: six decades without farming or building left the closed core one of the most valuable wilderness areas in central Europe, and the edge paths look straight into it.

The Ohře valley below Klášterec and Kadaň gives river routes with volcanic bluffs above; the southern and western edges around Valeč and Chyše — chateau villages on the slope — offer open, empty walking with long views into hills you cannot enter. Check current access maps: some edge zones open on weekends.