Although the latest bank vaults are built to be disassembled more easily (while still being ultra-secure), historically, bank vaults were built to last. Forever. As a result, some of them will survive almost anything. Even a nuclear blast. In fact, it was two Mosler bank vaults at the Teikoku Bank — and only those two bank vaults — that were left standing after Hiroshima was hit by an atomic bomb in 1945. In 1957, the U.S. also blasted a bank vault during nuclear testing in Nevada. The 37-kiloton nuke merely loosened the vault's trim.