Why do people continue to live in places they know to be dangerous?

　　Rahmad Hasan lost everything in the December 26 tsunami1. The waves took his family, his home and his livelihood2. “There’s nothing for me here anymore,” he says sitting in a refugee camp3 in Banda Aceh. “I’m getting out of here. Going someplace safer. Maybe I can start again.”

　　Despite the seeming common sense4 of Hasan’s desire to leave a disaster area, many people around the world continue to live in places they know to be unsafe. Towns grow at the feet of active volcanoes, cities build walls to hold back the sea, and skyscrapers5 continue to rise in earthquake zones.

　　One of the most extreme6 examples of people refusing to move in the face of impending7 disaster8 is the Netherlands. Known as the “low countries” because much of the land is now below sea level, many of the country’s largest cities are kept dry only by huge walls holding back the sea. In 1995, heavy rainfall nearly caused disaster, but the walls were just strong enough. “The fact is we can build all the walls we want,” says one engineer in Rotterdam. “But sooner or later, they’ll fail.”

　　San Francisco offers another case. In 1906, a huge earthquake destroyed the city: the buildings which weren’t knocked down by the quake, burned in the ensuing9 fire. But that quake wasn’t a one-off10 event: geologists11 say major quakes have occurred in the area approximately once every hundred years. This means that San Francisco is due for another catastrophe12 any day.

　　You’d think that this would cause people to move away, but the opposite is happening: every day brings new people to San Francisco, and house prices in the city have never been higher.

　　“Basically we try not to think about it too much,” says San Francisco resident Paul Lewis. “It’s a wonderful place to live, and I’d hate to think that it could all disappear tomorrow.”