The Kawah Ijen Volcano, East Java, Indonesia. Ijen is a 20 kilometers wide caldera, which houses more volcanoes in it. One of them is the Kawah Ijen volcano, which is filled with sulfur. When it burns the blue flames appear – the site is especially amazing at night.
Although the surroundings look rather unfriendly – an acid lake and petrified sulfur in the caldera – they are useful. The Ijen caldera is used as the coffee plantations, since the soil is very fertile. And the sulfur mine extracts the minerals. The site is also frequently visited by the tourists.
Indonesia’s Kawah Ijen volcano, located near the eastern tip of Java island, is a relatively ordinary volcano by day. OK so it’s kind of terrifying, as most volcanoes are, but there’s nothing about it that outwardly separates it from any of the other hundreds of volcanoes in this island country.
To learn why, you’ll need to head to the base of the volcano just after midnight, and hike up and into the volcano’s crater. It’s no easy task—you’ll trek more than four miles and ascend to heights of nearly 10,000 feet, with only the light of the moon to guide you—and that’s if it’s out.