On August 6, 1945 the atomic bomb was dropped on Japan and the world stood back horrified at the destructive force that man had created with nature and technology. Tens of thousands of people were killed, most of which by terrible burns and radiation poisoning. Everyone thought that the ultimate military weapon had been discover short of the wrath of god, but they were wrong.
In 1952 the first Hydrogen bomb was tested in Enewetok. Enewetok is an island that was originally given to Japan by the League of Nations. It was later captured during World War II and designated as a nuclear test site. Of course before the testing began the islands inhabitants were evacuated. It was later deemed safe to come back there and resume life in 1980. The bomb which was nicknamed "Mike" had a mushroom cloud eight miles across and twenty seven miles tall and the canopy was 100 miles across. It made a crater two hundred feet deep and six thousand five hundred feet across. Eighty million tons of Earth was vaporized. In comparison the atomic bomb to the hydrogen bomb is a match to a stick of dynamite. .
In 1953 the USSR (or Russia now a days) detonated a hydrogen bomb of their own. Later Great Britain, France, and China tested hydrogen bombs of their own. This created a sort of "nuclear club-nations". The requirements for this so-called "club" is that you must have nuclear capabilities and willingly admitting to stockpiling these bombs.
The way that this bomb works is very complicated. But the bang for the buck you get out of one of these things is literally going to stop your enemy "dead" in his tracks. The reaction starts with fusion of the hydrogen isotopes. An isotope is one of two or more atoms having the same atomic number but differing in atomic weight and mass number. This fusion creates heavier elements because of the number of lighter elements joined together. This difference in mass creates energy. This is called an endothermic reaction.