The second nuclear bomb that the US dropped on Nagasaki was called Fat Man and was an implosion-type device with a plutonium core. With its blast radius of 1 mile, this giant of a weapon managed to kill about 39000 people, and injure more than 25000.

This devastating bomb consisted of this starting from the inside and outwards:
- A polonium-berryllium initiator
- A hollow plutonium sphere
- Uranium 238
- Conventional explosives to ensure a huge impact

Tail fins were put on the bomb to intend for it to stabilize during descent. A miscalculation of these fins led to the bomb falling down from the sky in a wobbling motion.