Ijen Volcano in Indonesia is one of the best and most complex treks in the world, from many perspective:
- it is a beauty of nature, with one of the greenest and acidic lakes in the world,
- a good hike, about 3km up, then 1km down the crater; and back,
- cultural, local people work exploiting a sulphur mine down in the crater,
- witness the blue lights, a very rare phenomenon,
- you can get inside an active volcano, and inhale the fumes first hand :).
Here’s my post from the hike:
“Ijen Volcano, Indonesia – one of the most extraordinary treks ever! Active volcano, with the largest highly acidic crater lake in the world, and a sulphur mining operation make it a great walk from both natural and cultural perspective.
I started the trek with a local guide at about 3am, once the security guards allowed all people to go up. They monitor the gas emissions, and sometimes nobody is allowed. I walked with the mine workers and other tourists for 3 km in a steep climb, then 1km inside the crater to arrive to the mine and lake level. 2,799m of altitude from sea level in a couple of hours. The rush is to see the “blue fire” by night, which is caused by volcano emissions of molten sulphuric lava and gases, not visible by day.
The mining operation is very basic: some ceramic pipes that direct the molten sulphur to the surface, where it cools down changing color from intense red/orange to yellow. The solid sulphur is collected by the mine workers by hand and transported in loads of 70-80kg back to the starting point – 1km up the crater, plus 3km to the base. They do about 2 runs per day for about $5 usd each, depending on the weight they carry (about 7 cents per kg).
The lake is very dangerous and nobody swims in it due to random burning hot water and gas emissions, high acidity, and quick sands right at the shore.”