The King of Bombs
Approximately four years after launching the first satellite into orbit, the Soviet Union conducted the largest nuclear detonation in history. "Tsar Bomba" (nicknamed "Big Ivan" by its designers) had an estimated yield of 50 Megatons -- nearly triple the yield of CASTLE BRAVO (the U.S.'s 1954 dry-fuel [Teller-Ulam design] thermonuclear device tested at Bikini Atoll). The test over Novaya Zemlya just before noon (Moscow time) on Oct. 30th, 1961, nearly knocked out of the sky the modified Tu-95 BEAR bomber that carried it. Its blast plume measured more than 40 miles (65km) high.
A two-minute video from Discovery Channel:
An eight-minute video on YouTube:
What's ironic is that a last-minute switch (replacing the Uranium tamper with one made of lead) was done to reduce its yield and subsequent fallout. If this change had not been made, the yield could have exceeded 100 Megatons.
Increased awareness of military facility locations, coupled with improved accuracy of missile delivery systems, made massive weapons like Tsar Bomba thankfully irrelevant.