German archaeologist Heinz-Juergen Beste has spent the past 14 years figuring out a hidden labyrinth underneath Rome’s Colosseum, and Smithsonian magazine explains his findings. “Its complexity was downright horrifying,” Beste says. The labyrinth, called the hypogeum, contained human-powered machinery that made animals and scenery appear from beneath a wooden floor as if by magic. While Colosseum spectators enjoyed prizes, pastries and wine, the workers in the hypogeum were subjected to disgusting smells and deafening noise, Beste says. Plus, they could be sentenced to fight to the death in the vast arena if they botched their duties. Following a $1.4 million renovation, the hypogeum opened to the public in October.