Cesky Dub, 463 43
Originally a basalt dike that used to stretch the length of 20 km from Světlá pod Ještědem to Bezděz; most of it has been exploited. In 1964, the Čertova Zeď was declared a national natural monument.
Locality: 5 km to the west of Český Dub.
Access: from Český Dub, direction towards Osečná, to the crossroads between Smržov and Kotel; from there, on foot along the marked trail.