The United States, Soviet Union, and United Kingdom signed the Limited Test Ban Treaty in 1963 that permitted only underground nuclear tests, but that hasn’t stopped footage from prior years to leak out. We’ve rounded up five unbelievable clips that show off the power of nuclear weapons. Continue reading to see them all.

5. Underground Detonation

Underground nuclear testing refers to test detonations of nuclear weapons that are performed underground. When the device being tested is buried at sufficient depth, the explosion may be contained, with no release of radioactive materials to the atmosphere. The extreme heat and pressure of an underground nuclear explosion causes changes in the surrounding rock. The rock closest to the location of the test is vaporised, forming a cavity. Further away, there are zones of crushed, cracked, and irreversibly strained rock. Following the explosion, the rock above the cavity may collapse, forming a rubble chimney. If this chimney reaches the surface, a bowl-shaped subsidence crater may form.

4. Castle Bravo

Castle Bravo was the code name given to the first U.S. test of a dry fuel thermonuclear hydrogen bomb device, detonated on March 1, 1954 at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. When Bravo was detonated, it formed a fireball almost four and a half miles (roughly 7 km) across within a second. This fireball was visible on Kwajalein atoll over 250 miles (400 km) away. The explosion left a crater 6,500 feet (2,000 m) in diameter and 250 feet (76 m) in depth. The mushroom cloud reached a height of 47,000 feet (14,000 m) and a diameter of 7 miles (11 km) in about a minute; it then reached a height of 130,000 feet (40 km) and 62 miles (100 km) in diameter in less than 10 minutes and was expanding at more than 100 metres per second (360 km/h; 220 mph).

3. Tsar Bomba

The Tsar Bomb was a three-stage Teller-Ulam design hydrogen bomb with a yield of 50 megatons (Mt).[5] This is equivalent to 1,400 times the combined power of the bombs that destroyed Hiroshima and Nagasaki,[6] 10 times the combined power of all the conventional explosives used in WWII, or one quarter of the estimated yield of the 1883 eruption of Krakatoa. 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. There is evidence that the Tsar Bomba had a number of third stages rather than a single very large one.

2. Underwater

An example of a deep underwater explosion is the Wahoo test, which was carried out in 1958 as part of Operation Hardtack I. The nuclear device was detonated at a depth of 500 ft (150 m) in deep water. There was little evidence of a fireball. The spray dome rose to a height of 900 ft (270 m). Gas from the bubble broke through the spray dome to form jets which shot out in all directions and reached heights of up to 1,700 ft (520 m). The base surge at its maximum size was 2.5 mi (4.0 km) in diameter and 1,000 ft (300 m) high.

1. Space

High-altitude nuclear explosions (HANE) have historically been nuclear explosions which take place above altitudes of 30 km, still inside the Earth’s atmosphere. Such explosions have been tests of nuclear weapons, used to determine the effects of the blast and radiation in the exoatmospheric environment. The highest was at an altitude of 540 km (335.5 mi). The only nations to detonate nuclear weapons in outer space are the United States and the Soviet Union. The U.S. program began in 1958 with the Hardtack Teak and Hardtack Orange shots, both 3.8 megatons.

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