The Manhattan project
The scientist given the most credit for the building of the atomic bomb is Robert Oppenheimer.
T.n.t ??
Given the power of modern atomic bombs, it is unlikely that a single atomic bomb could destroy the world. It is doubtful that a single atomic bomb could cause irreparable damage to civilization (given humanity's spread across the planet etc)
Robert Oppenheimer
No. By the time the US dropped the atomic bomb on Japan, Germany had already surrendered. While Germany did have a nuclear weapons program during the war, it did not actually get to the point that they were capable of building a working bomb.
Oppenheimer......................
The Manhattan Project
Building the first atomic bomb.
The building of the atomic bomb was known as the Manhattan Project. It was a research and development project during World War II that produced the first nuclear weapons.
Oppenheimer had the codename James Oberhelm; Fermi's name was Henry Farmer; and Hans Bethe was Howard Battle.
Robert Oppenheimer
Little Boy was the code name for the bomb that hit Hiroshima at the end of WW2.