The largest bomb ever built and detonated was AN602 (Tsar Bomba) in 1961. It produced an explosion equivalent to 50 million tons of TNT. The fireball was 5 miles wide, and the blast radius was more than 22 miles, capable of destroying even the largest city in a single blast. In comparison, it was 2400 times stronger than the bomb used to destroy Hiroshima, and due to a triple-stage fusion-boosted process, was about the same physical size. The mushroom cloud was 7 times higher than Mt. Everest. Even though it was detonated 4 miles above the Earth’s surface, the seismic shock measured as a 5.25 on the Richter scale, and traveled all the way around the planet 3 times. Atmospheric focusing carried the blast damage to more than 600 miles away from ground zero. It generated 1.4% as much energy as the sun itself. The entire explosion took less than a half a second.
It was the single most powerful device ever created by mankind. And do you want to know the scary part?
They only ran it at half yeild; it was designed to yeild a 100 MegaTon explosion.