Landsides are one of the world's most costly natural disasters, yet people continue to build in slide-prone areas. What determines why one area is more susceptible to landslides than another?
Unlike many other natural disasters, landslides offer no real advance warning. Often triggered by heavy rainfall, landslides pose a danger to those who live in areas where humans have altered the local geography. In addition to video taken of landslides in progress, this episode highlights efforts being made to protect motorists from rocks and boulders falling onto roadways.