Nevada is site of first-ever underground nuclear explosion - Sep 19, 1957 - HISTORY.com

History.com has this for 19 September:

http://www.history.com/this-day-in-history/nevada-is-site-of-first-ever-underground-nuclear-explosion?cmpid=email-hist-tdih-2016-0919-09192016&om_rid=847fd754baf09b7865bbc1fb225e1b1b26c8bf50caf45bc6e6b7fec8944a2985&om_mid=91339491&kx_EmailCampaignID=7189&kx_EmailCampaignName=email-hist-tdih-2016-0919-09192016&kx_EmailRecipientID=847fd754baf09b7865bbc1fb225e1b1b26c8bf50caf45bc6e6b7fec8944a2985