A great place to stop off for travellers en route to the holiday resort of Lake Toba, the town of Berestagi is famed not only for its passion fruit, but also for the two active volcanoes on its doorstep: Gunung Sibayak and Gunung Sinabung. Gunung Sibayak boasts fantastic hot springs where visitors can relax and unwind in the warm waters which are believed to have therapeutic properties. More active travellers can climb this mountain instead, earning breathtaking views over the island of Sumatra from the top. This is the most commonly climbed volcano in Sumatra as the hike to the top is comparatively easy, with beautiful and unusual scenery to enjoy along the way. It only takes about two hours and can be done safely without a guide, although having someone along who can explain the geological significance of the place and identify the local flora and fauna is a bonus. The volcano is still active and the boiling sulphur makes the smell in the area unpleasant but you get used to it quite fast and gradually stop noticing. Its fun to head to the hot springs after the hike - the pools range in temperature from pleasantly warm to boiling hot so make sure you test the water and don't burn yourself.