Tsomgo (Changu) Lake, Sikkim

A glacial lake at 3,753 m on the road from Gangtok towards the Nathu La pass on the Tibet border. It's sacred to Sikkimese Buddhists and Hindus, and changes colour with the seasons: frozen in winter, surrounded by flowering rhododendrons and primulas in spring. Yaks wait by the shore to give rides.

Foreigners need a protected area permit, arranged through a registered travel agent in Gangtok, and must travel with an agency; you can't go independently. It's a day trip of about 2 to 3 hours each way. Take warm clothes, as it's cold even in summer, and watch for altitude sickness. Nathu La itself is closed to foreigners.