A man inspects a sinkhole formed in a house on July 19, 2011, north of Guatemala City. When neighbors heard the loud boom overnight they thought a cooking gas canister had detonated. Instead they found a deep sinkhole the size of a large pot inside a home under a woman's bed. The sinkhole was 40 feet deep and 32 inches in diameter. Police, members of the country's natural disaster office and water utility company officials came to visit the site. Sinkholes, formed by the natural process of erosion, can be gradual but are often sudden. Guatemala City, built on volcanic deposits, is especially prone to sinkholes, often blamed on a leaky sewer system or on heavy rain. JOHAN ORDONEZ/AFP/Getty Images