Castle Bravo is named after the atomic bomb that was unsuccessfully used to try to kill Godzilla in 1954.
Castle Bravo was constructed by Monarch as a means of researching and understanding Godzilla on his home turf. The outpost eventually became the flagship of Monarch, housing many of Monarch's researchers, scientists, and its large personal in the massive facility. Disguised as an oil rig, it splits open to reveal a vertical shaft leading to a massive cavern.
The outpost is divided into 3 levels: above sea-level, sea-level, and below sea-level. The sub-level facility is protected with numerous manual-controlled armaments and specially designed weapons produced by Monarch as a means of better protecting the facility from an attack from Godzilla or another sea-dwelling Titan. The sea-level part of the facility has a large cylinder opening at the top leading down into the facility.
The facility is seen to house numerous Monarch Submarines, modified VTOL helicopters, and a large arsenal of submersible vessels. Also, contained on Level Two of Castle Bravo are the remains of several Titans: some only bones and a few others still whole, including the remains of the MUTOs and MUTO Prime.
- In the Godzilla: King of the Monsters - The Official Movie Novelization, the remains of a Titan known as Margygr are contained in the outpost after being found in the Arctic, killed by another Titan. It's also revealed by Sam Coleman that the Titan remains are being studied to potentially sequence their DNA and insert certain traits they possess into other sequences.