Sinkhole rain. An analysis of a case of sinkhole formation under a retention pond due to a large amount of rain can be seen in a sinkhole collapse study. Sinkholes have been used for centuries as disposal sites for various forms of waste. A consequence of this is the pollution of groundwater resources, with serious health implications in such areas. The Maya civilization sometimes used sinkholes in the Yucatán Peninsula (known as cenotes) as places to deposit precious items and human sacrifices. When sinkholes are very deep or connected to caves, they may offer challenges for experienced cavers or, when water-filled,
2007 Guatemala City sinkhole on the city's aging sewerage system, and have speculated that more piping failures are likely to develop unless action is taken. Several rainstorms also contributed to the sinkhole's collapse, as stormwater percolated into the ground, further dissolving the rocks beneath Guatemala City. Citizens of Guatemala City near the sinkhole also reported hearing rumblings a few weeks before its collapse. The INSIVUMEH (Guatemala's seismology institute) had placed a seismic meter there before the disaster; a robotic camera system was supposed to enter the cavity, but the disaster occurred first. On February 23, 2007, the sinkhole collapsed, forming a very large, deep