Lying right in the middle of the province, jewel-like Danau Toba is Southeast Asia’s largest freshwater lake, and at 525m possibly the world’s deepest, too. It was formed about 80,000 years ago by a colossal volcanic eruption: the caldera that was created eventually buckled under the pressure and collapsed in on itself, the high-sided basin that remained filling with water to form the lake. A second, smaller volcanic eruption, 50,000 years after the first, created an island the size of Singapore in the middle of the lake. This island, Pulau Samosir, is the cultural and spiritual heartland of the Toba Batak people and one of the most fascinating, pleasant and laidback spots in Indonesia.
Pulau Samosir is arguably the best spot in Sumatra to relax for a few days on a hammock by the azure water. Most tourists make for the eastern shores of Samosir where there’s a string of enjoyable resorts, the main one being Tuk Tuk, housing plenty of hotels, restaurants and bars. From here you can trek into the deforested hills within the centre of Samosir or circle the island’s coastline by motorbike, calling in at tiny Batak villages that have flamboyant tombs and distinctive concave-roofed houses, as well as the island’s cultural centre of Simanindo, on Samosir’s northern shore.