Lake Toba is one of Indonesia's most spectacular sights - a remarkable volcanic crator set in the middle of North Sumatra, 176km from Medan.
The lake is huge (the largest in South East Asia), occupying the culdera of a giant volcano that colapsed on itself after a massive eruption 100,000 years ago.
In comparison, Krakatau's 1883 effort was little more than a belch.
Toba is also the worlds deepest lake at over 450m, though accurate surveys of the lake floor have yet to be made.
Samosir, the wedge shaped island in the middle of the lake , is thought to have been created by subsequent upheavals between 30,000 and 75,000 years ago.
Samosir has long been North Sumatra's premier attraction for travelers and has an abundant supply of accommodation and eateries ringing the shoreline. Actually Samosir isn't realy an island.
It was only separated from the mainland when the Dutch dug a canal accross the narrow istmus at Panguran. At the time this caused some consternation amongst the Bataks, who feared that Samosir might now slide into the lake. The main town in the area is Parapat, on the eastern shore of Lake Toba.
Remarkably no important rivers flow into Toba although the Asahan river which flows out of the southern end of the lake is large enough to provide hydro electric power for an aluminium plant on the east coast of Sumatra. The Asahan is also home for some quite challenging white water rafting and trips can easily be arranged for the adventurous.
At the north end of Lake Toba is the spectacular Sipisopiso (like a knife) waterfall, which falls 120m, apparently from a cave at the very edge of the plateau, and then becomes a gushing stream which enters the lake at the village of Tongging. . . . >>> more . . .