5 Most Dangerous Places on Earth

• Lake Nyos, Cameroon

A silent killer lurks beneath the surface of this West African lake. A pocket of magma deep below the lake bed leaks carbon dioxide into the lake above. Under the pressure of 650 feet (200 meters) of water, this carbon dioxide stays dissolved, much like the carbonation in a bottle of soda.

But on the night of August 21, 1986, the water in the lake abruptly turned over, and the now-depressurized carbon dioxide exploded upward like a shaken soft drink. The resulting carbon dioxide cloud rushed downhill, asphyxiating 1,700 people and thousands more animals. In the 15 miles (24 kilometers) of valleys below the lake, almost nothing survived.

Today, pipes are used to siphon carbon dioxide-rich water from the bottom of Lake Nyos. The pipes prevent carbon dioxide buildup, but that doesn't make Lake Nyos entirely safe, said George Kling, a University of Michigan geochemist who was on the team that originally investigated the 1986 disaster.

• Miami, Florida

No one can predict where a hurricane will hit next, but south Florida is always a reasonable bet. The U.S. Geological Survey estimates the southern tip of Florida can expect more than 60 hurricanes over a 100-year period. And in 2008, sustainability company SustainLane ranked Miami as the most risky city for natural disasters in the United States.

Hurricane destruction in Miami and the nearby Florida Keys is nothing new. In 1926, the Great Miami Hurricane destroyed or damaged every building in downtown Miami and killed at least 373 people, according to the Red Cross. Less than 10 years later, the Labor Day hurricane of 1935 killed 408 people in the Florida Keys. In 1960, Hurricane Donna roared through the Keys and South Florida, bringing with it 11 to 15-foot storm surges.

Perhaps the most famous hurricane to hit south Florida was 1992's Hurricane Andrew . Andrew blasted through Florida as a Category 4 storm with winds so high they broke measurement instruments. According to the National Oceanic and Atmospheric Administration, Andrew killed 23 people in the United States. The destruction totaled more than $26.5 billion.

• The Sahel region of Africa

Drought often doesn't get as much attention as other natural disasters, but it can be a killer. According to the United Nations Environmental Programme, more than 100,000 people died because of drought in the Sahel region of Africa from 1972 to 1984. Another 750,000 were unable to grow their own crops and were completely dependent on food aid.

The arid Sahel region borders the Sahara Desert , stretching across northern Africa through Mauritania, Senegal, Mali, Niger, Burkina Faso, Nigeria, Chad, Sudan, Algeria, Ethiopia and Eritrea. According to the U.N., human exploitation of the area's limited water is causing desertification, raising the risk of future drought and famine.

• Guatemala

Central America gets hit by a triple threat of natural disasters: earthquakes, hurricanes and mudslides.
Along with the western coast of North and South America, Central America lies on the Ring of Fire, a seismically active loop that encircles the Pacific Ocean. Guatemala isn't the only country affected, but it's been hit hard: In 1976, a 7.5-magnitude earthquake killed 23,000 people, according to the USGS. Thanks to the country's mountainous terrain, landslides hampered transportation and rescue efforts.

The combination of topography and weather can be deadly as well. Heavy rains can saturate hillsides, leading to devastating mudslides. In 2005, the remnants of Hurricane Stan soaked Guatemala, El Salvador and southern Mexico, causing more than 900 mudslides. Entire villages were buried; one, Panabaj, was declared a cemetery after officials gave up hope of excavating the bodies of 300 missing villagers. The exact death toll is unknown, but some estimates suggest that up to 2,000 people lost their lives.

• Java and Sumatra, Indonesia

These two Indonesia islands face perhaps more natural disaster hazards than anywhere else. Droughts, floods, earthquakes, landslides, volcanoes and tsunamis all threaten Indonesia, and Java and Sumatra have the highest risk, according to the Center for Hazards and Risk Research at Columbia University.

The most famous disaster to hit Indonesia is the 2004 Indian Ocean tsunami , which killed an estimated 227,898 people after a 9.1-magnitude earthquake triggered the enormous wave. Indonesia was hardest hit among the affected Southeast Asian countries, with over 130,000 people confirmed dead.

But smaller disasters cause more regular suffering. Between 1907 and 2004 (before the tsunami), droughts killed 9,329 Indonesians, according to the Columbia University group. Volcanoes killed 17,945 people in the same time period, and earthquakes killed 21,856. One of the most famous eruptions in history, of the volcano Krakatoa, occurred in the Sunda Strait between the two islands. And as recently as this February, floods drove thousands of west Java residents from their homes, and a landslide in the village of Tenjolaya killed dozens.