Claim: Kosmos 419 was launched at Baikonur, the largest operational space launch facility, on May 10, 1971 but was unfortunately a launch failure.
Evidence: Baikonur 81/23 The Cosmodrome is the world's first spaceport for orbital and human launches and the largest (in area) operational space launch facility. 10 May 1971, 16:58:42 (1971-05-10UTC16:58:42Z) UTC Launch failure