A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The 2010 Guatemala City sinkhole (above) formed suddenly in May of that year; torrential rains from Tropical Storm Agatha and a bad drainage system were blamed for its creation. It swallowed a three-story building and a house; it measured approximately 20 m (66 ft) wide and 30 m (98 ft) deep. The Guatemala City holes are instead an example of “piping pseudokarst”, created by the collapse of large cavities that had developed in the weak, crumbly Quaternary volcanic deposits underlying the city. Continue reading for more.