Janek Pawlik, age 13, of St. Catharines, Ontario, Canada, for his question:

WHAT IS A RIFT VALLEY?

Great Rift Valley is a series of valleys that cut through a great deal of eastern Africa. The area extends from Syria in the southwestern part of Asia to Mozambique in the southeastern part of Africa.

The walls of the valley are steep, often rising one mile high in some places. Most parts are from 20 to 30 miles wide.

Land shifted in prehistoric times to form the valley. Lava came from the earth and formed plateaus along the valley sides and volcanoes in and near the valley. The higher plateaus have mild climates and some of Africa's best farmland. The River Jordan, the Red Sea and lakes Albert, Edward, Nyasa and Tanganyika are in the valley. Steep walls are obstacles to east west travel.