What formed devil's tower?

Devil's Tower, located in Wyoming, is a monolithic butte formed from an igneous intrusion of volcanic rock. Approximately 50 million years ago, magma from beneath the Earth's surface cooled and solidified underground, creating a large column of granite. Erosion over time removed the surrounding softer sedimentary rock, exposing the tower's distinctive columnar jointing. This unique geological formation is now a protected national monument and holds cultural significance for several Native American tribes.