While in Gillette we traveled to Devils Tower National Monument in northeast Wyoming. President Theodore Roosevelt declared it the first national monument in 1906. There are several legends and hypotheses about the origin of the tower but no one knows for sure how it was formed. It rises 867 feet from its base and is an igneous intrusion. As the magma cooled hexagonal columns formed. Devils Tower did not protrude above the landscape until the overlying sedimentary rocks eroded away. Portions of the tower have broken off due to the effect of ice freezing in cracks. Piles of broken columns lie at the base of the tower indicating it was once larger than it is today. We enjoyed walking the trail at the base of the tower.
Devils Tower is a popular climbing location. While we were there we saw four or five groups of climbers on the monument.