The view from the rim of Mount Ijen (2800m) is among the very best to be had in Indonesia. Bounded by sheer cliffs, its crater holds a 200-meter-deep lake steaming with turquoise acid water, its shoreline striped with a bright yellow sulphuric lining. As well as otherworldly vistas, some of the world’s toughest workers may be seen here, battling toxic fumes, treacherous terrain and hauling 70kg sacks brimming with sulphur deposits. Ijen can be reached from Banyuwangi or Bondowoso, although both routes entail sections of dodgy roads and a 1hr 30min drive through forests and coffee plantations to the trailhead at Pos Paltuding. There, hikers must register their names at the PHKA Office and pay the admission fee before making the 1–1hr 30min hike to the lip of the crater. Although not strictly necessary, a local guide is recommended, especially when making the 30min descent into the crater itself, where both toxic fumes and a steep path can be dangerous. The relatively dry months from April to October are ideal for the hike. Transportation to Pos Paltuding is easily arranged in Banyuwangi.