VANITY FAIR: It was like something out of M. Night Shyamalan’s Signs. A gaping, perfectly circular sinkhole appeared Sunday in Guatemala City, devouring a three-story building and killing at least one man in the process. The gargantuan cavity appears to be about 60 feet wide and 30 stories deep, according to National Geographic. If it wasn’t caused by aliens, how did the sinkhole form? Where did its insides go? And why the heck is it so round? We consulted David Bercovici and Mark Brandon, both professors of geology and geophysics at Yale University, to fill in the gaps in our sinkhole knowledge. Find their condensed and combined answers below. MORE