The Book of Revelation says the end of the world will be announced with the sound of seven trumpets. Each blowing of the trumpet brings a new apocalyptic event. After the seventh trumpet: armageddon. For centuries, people have reported low-frequency hums, the crack of thunder on a clear day and the sound of cannon-fire in the middle of nowhere. Mysterious sounds have been heard at the bottom of the ocean and in outer space. And they’ve been heard long before modern machines and industry. Recently, people have been recording and sharing videos of these loud, unnatural sounds. And some of them? They sound a lot like trumpets.