January 27, 2017 all-day
27 January 1967. Three American astronauts, Virgil I. Grissom, Edward H. White and Roger B. Chaffee, died when fire suddenly broke out at 6: 31 PM, EST, in Apollo I during a launching simulation test, as it stood on the ground at Cape Kennedy, FL. First launching in the Apollo program had been scheduled for 27 February 1967.
Image courtesy of Wikimedia Commons.