Driving on Lake Baikal (world's oldest lake)

Lake Baikal is the world's oldest lake. It is said to be 25 million years old. It is the same size as the state of Maryland. Its widest point is nearly 400 miles. In certain areas the waters are more than a mile deep. It is frozen solid for about four months out of the year, during which times you can safely (but with caution, because seismic activity, storms and underwater gases can cause temporary and permanent danger zones) drive even large vehicles clear across the lake, as seen below, but no matter how frozen it is you can always hear the ice creaking and cracking beneath your feet. The frozen lake is always in motion.

We drove for five hours on the lake, from the village of Khuzhir to the northernmost tip and back, with no problems, but our driver did stop once to test a potential danger zone. He approached the rift and kicked down swiftly with his boot, a strategy that didn't exactly seem foolproof [edit (16.04.11) photos of suspect safety test in progress, added to end of post].