Just inside Wyoming, Devils Tower is a 867 foot tower of column basalt formed from cooled magma underground. The surrounding terrain has since eroded away and now the rock is exposed and above ground. Devils Tower is a climbing paradise with over 220 routes and 5,000 climbers a year attempting it. There is a nice 1.3 mile trail around the monument that should be part of any visit.
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Devils Tower National Monument
Approaching the monument