What was the bomb actually made of? That's the part I don't get. What made up the 27 tonnes of bomb to produce the yield equivalent of a detonation of 57 million tonnes of TNT?
From it's wiki page:
The Tsar Bomba was a three-stage Teller–Ulam design hydrogen bomb with a Nuclear weapon yield of 50 megatons (Mt). This is equivalent to 1,400 times the combined power of the two nuclear explosives used in World War II (Little Boy (13-18 kilotons) and Fat Man (21 kilotons), the bombs that destroyed Hiroshima and Nagasaki)., or 10 times the combined power of all the explosives used in WWII. A three-stage H-bomb uses a fission bomb primary to compress a thermonuclear secondary, as in most H-bombs, and then uses energy from the resulting explosion to compress a much larger additional thermonuclear stage. However, there is evidence that the Tsar Bomba had a number of third stages rather than a single very large one.
The initial three-stage design was capable of approximately 100 Mt, but would have caused too much radioactive fallout. To limit fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper (which greatly amplifies the reaction by fissioning uranium atoms with fast neutrons from fusion reaction). This eliminated fast fission by the fusion-stage neutrons, so that approximately 97% of the total energy resulted from fusion alone (as such, it was one of the "cleanest" nuclear bombs ever created, generating a very low amount of fallout relative to its yield). There was a strong incentive for this modification since most of the fallout from a test of the bomb would fall on populated Soviet territory.
The components were designed by a team of physicists headed by Academician Julii Borisovich Khariton and including Andrei Sakharov, Victor Adamsky, Yuri Babayev, Yuri Smirnov, and Yuri Trutnev. Shortly after the Tsar Bomba was detonated, Sakharov began speaking out against nuclear weapons, which culminated in his becoming a dissident.