The Devils Tower National Monument in the north-eastern corner of Wyoming was declared the first national monument in the United States. Devils Tower, a conical flattened mountain from column basalt, rises up 265 m / 867 feet clearly visible out of the prairie. Molten magma was forced into sedimentary rocks above it and cooled underground. As it cooled it contracted and fractured into columns. Over millions of years, erosion of the sedimentary rocks exposed Devils Tower. Wind and weather gnaw at the mountains, and the columns break off piece by piece. You can follow a two kilometres long loop around the tower, where you can watch climbers during summer.
In the afternoon we cant resist to buy cowboy boots in Spearfish thats already in South Dakota. A short detour guides us through 25 km long Spearfish Canyon. The road parallels a small creek that carved the canyon years ago. The canyon is part of the Black Hills, a low mountain range between Wyoming and South Dakota. Here you can find many of the attractions in this area, but best starting point for tours is Rapid City, with 62,000 inhabitants the largest city within a radius of some hundred miles.