Kawah Ijen

Kawah Ijen is a volcano at the eastern end of Java known for two remarkable sights. By night, gases seeping from vents in its crater ignite on contact with the air and burn in flames of an eerie electric blue, one of only a handful of places on earth where this can be seen, drawing hikers who climb in darkness to witness it. By day the crater reveals a lake of extraordinary beauty and danger: a vast expanse of milky turquoise water that is in fact intensely acidic, one of the largest such lakes in the world. Amid all this, miners still work the crater by hand, hacking bright yellow sulphur from the vents and carrying crushing loads up and out, one of the most gruelling jobs anywhere. The climb is done before dawn to catch the blue fire and then the sunrise over the lake.

What you actually see

• The blue flames - the electric-blue burning sulphur gases seen in the crater at night.
• The acid crater lake - the vast milky-turquoise lake, beautiful and highly acidic.
• The sulphur miners - the labourers hauling loads of yellow sulphur from the crater.
• The sunrise - the light breaking over the crater and the surrounding volcanoes.

When to go

April to October, the dry season, is safest and clearest; the trek starts in the small hours to reach the blue flames before dawn. The blue fire is only visible in darkness, so timing is everything. Volcanic gas conditions can close the crater floor at any time.

Honest expectations

The crater emits toxic sulphurous gas, and descending to the blue flames means entering that gas, which is genuinely hazardous; a proper gas mask, not a cloth, is essential and many guides now discourage or restrict the descent. The pre-dawn climb is steep and cold, and the return is in fierce sun. Conditions and access change with volcanic activity. Treat the miners with respect and do not turn their hardship into a photo prop.

Nearby

Banyuwangi and the ferry to Bali are close; Mount Bromo lies to the west across East Java.