North Korea now has a museum for its bombs. The National Defence Revolution Museum, which opened on Sunday, is the country’s first dedicated exclusively to military hardware, from rifles to intercontinental ballistic missiles (ICBMs). Observers say it is also intended to send a message to Washington and Seoul, serve as a permanent showroom for the North’s arms exports and visibly enshrine its nuclear programme as an irreversible part of state policy. Third-generation ruler Kim Jong-un cut the...