March Field Air Museum has the casing of a B61 gravity nuclear bomb. Here are a few photos of the weapon along with a description.
B61 Thermo-nuclear bomb
weight: 695-716 lbs
Length: (including fins) 11 ft 9.5 in.
Number in service: 600 (tactical) 750 (strategic)
Designed for the United States Air Force by the Los Alamos Scientific Laboratory, the B61 was developed to provide a lightweight nuclear weapon capable of being carried on external mounts by high-performance aircraft.
The B61’s variable yield, from 0.3 to 34 kilotons permits the weapon to be adjusted for use against smaller area tactical battlefield targets or larger strategic counter-force (opposing military or industrial) and counter-value (population or political targets.
Museum also has display model of CBU-87 cluster bomb.