Not too many decades ago, Nevada was the main U.S. test site for nuclear weapons.  Above ground explosions could sometimes be seen from Las Vegas (makes the Mirage volcano seem kind of wimpy).  The Atomic Testing Museum has loads of information about this era.  It's a very strange place, but is also very interesting and informative.  Make sure to see the Ground Zero Theater, which \"mimics a concrete bunker and features a large screen show that includes the history of test effects from a variety of viewpoints.\"