Devils Tower National Monument is a must see on any road trip in South Dakota! In fact, you can think of Chris Bolhuis while you are listening, as he is currently teaching 26 lucky high school students at Devils Tower at the moment!The geology of this amazing spectacle has it all - beautiful sedimentary rocks, unique volcanic rocks, and great columnar joints that make the Tower look utterly striking. Devils Tower is a unique rock called a phonolite, and it represents some part of an ancient volcano's plumbing system - a 40 million year old volcano! As usual Like, Subscribe, and leave us a Rating, but don't forget to share PlanetGeo with someone you know!——————————————————Instagram: @planetgeocastTwitter: @planetgeocastFacebook: @planetgeocastEmail: planetgeocast@gmail.comWebsite: https://planetgeocast.com/