On the 23rd of February 2007, a 330 foot deep sinkhole swallowed up over a dozen homes in a crowded neighborhood in Guatemala City. Over 1000 people were evacuated and two people were killed. The giant hole emitted a foul stench, tremors and loud noises. The authorities blamed the sinkhole on a ruptured underground sewage flow. Sinkholes are caused by changing geological conditions or by a failure to maintain aging underground pipes and sewage systems, but the common factor in both is usually water. Ground underlain with carbonate bedrock - limestone for example - is most prone to sinking because the bedrock erodes with repeated exposure to water. The rock corrodes and the sediment swells with water and eventually everything reaches a critical mass point. The sinkhole phenomenon appears to be intensifying all over the world as ground water continues to face depletion and earthquakes weaken substrata layers of earth.