Volcanoes, earthquakes, and tornadoes all can cause enormous damage, and predicting where and when they will strike is of great importance. Volcanologist Dr. Marie Edmonds has devised sensors that monitor the underground activity of magma to better predict future eruptions on the Caribbean island of Monserrat, the site of the massive 1995 eruption captured for this film. Geophysicist Dr. Ross Stein studied the earthquake repair records in Istanbul's Hagia Sophia over the centuries to find clues about the history of earthquakes in Turkey. He discovers a pattern in quakes along the long North Anatolian Fault system, including the massively destructive quake at Izmit in 1999, and predicts the next earthquake just a few miles south of Istanbul. Dr. Joshua Wurman and his team chase tornados in trucks equipped with Doppler radar in an attempt to probe the interior of a tornado just as it is born. Written by Brian Greenhalgh

The Serengeti is a huge area of grassland in Tanzania, Africa. Once a year, in the time of drought, about two million herd animals like antelopes travel north to feed and mate before moving south again, when plants there begin to blossom. Written by Julian Reischl julianreischl@mac.com