Diefenbunker Entrance
Mk.4 Atomic Bomb
The Mark 4 nuclear bomb was an American nuclear bomb design produced starting in 1949 and in use until 1953. It was 60 inches (1.5 m) in diameter and 128 inches (3.3 m) long, the same basic dimensions as Mark 3. It weighed slightly more at 10,800 to 10,900 pounds (4,900 to 4,940 kg), depending on the specific Mark 4 version.