2. Kawah Ijen, Indonesia
Known also as the Ijen Crater, the Kawah Iljen trek is just three kilometers long but presents one of the more challenging trails you will encounter in this region. The trail snakes along a mountain side, all the way to the main attraction – a blue-green crater lake.
Sulfur Mining_ Kawah Ijen_-_Indonesia | Semhur
The blue-green light from the crater is not from the lava directly, but actually comes from the interaction of heat, regular air, and sulfuric gases. This would also account for the funky smell when you are finally close enough to Kawa Iljen. Trek starts at the base camp at Paltuding.
3. MacRitchie Reservoir, Singapore
The MacRitchie Reservoir Park is one of the last few swathes of green in this bustlingly busy city-state, and is a perfect getaway for trekkers who want to see how Singapore looked before it transformed itself into an Asian power in its own right.
What you will see when you visit is a largely unspoiled rainforest and a reserve that is easy to access, and largely open to tourists and serious trekkers alike. Go here if you just want an easy trek, and you’d like for food kiosks to be nearby. You can go as short as two miles, or walk the entire seven miles – that would be completely up to you.