Lake Toba is the largest volcanic lake in the world, filling a caldera left by an eruption so massive it changed the planet's climate for years. None of that history is obvious from the water's edge, which just looks impossibly calm and blue.
An island inside the lake
At the centre of Toba sits Samosir, an island roughly the size of Singapore, formed by the same eruption that created the lake around it. Getting there means a short ferry crossing, after which the pace of the trip changes completely.
Getting lost on a scooter
Samosir is best explored the same way as Pulau Weh: rent a scooter and follow whatever road looks interesting. Traditional Batak villages with their distinctive saddle-roofed houses, hot springs at Pangururan, and quiet lakeside stretches with nobody else around are all within reach of each other.
Toba Batak culture
Samosir is the heartland of Toba Batak culture, distinct from the Karo Batak villages around Berastagi. Tomok and Ambarita hold traditional houses, old stone chairs once used for village councils, and museums worth an hour of anyone's time.
Lake Toba pairs naturally with Berastagi as part of a longer route south from Bukit Lawang, cooler air and water both, before heading back to Medan.