Devils Tower Becomes First American National Monument
On September 24, 1906, President Theodore Roosevelt declared Devils Tower in Wyoming to be the first National Monument under the Antiquities Act.
Devils Tower is a nearly vertical monolith of volcanic rock which rises 1,267 feet above the Belle Fourche River, which meanders below it. This rock formation is believed to be about 40 million years old. Once buried, erosion slowly stripped away the softer soils that once covered this impressive landmark.