Bořeň is a structure similar to the butte in what mountains in Wyoming?
Bořeň:  It is a structure similar to the Devils Tower in Wyoming, and is the largest phonolite structure of its kind in Europe. Devils Tower: Devils Tower (also Bear Lodge Butte) is a laccolithic butte composed of igneous rock in the Bear Lodge Mountains (part of the Black Hills) near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River.
Bear Lodge Mountains