While the ferry is about to dock, the evening call for prayer sounds from a mosque in the distance with Kawah Ijen as the backdrop. We’ve crossed the narrow Bali Strait to East Java, the islands most natural region and home to no less than forty-five active vulcanoes. Mount Semeru is the highest and together with Merapi the most active, Bromo may be the most beautiful, but on this trip we’ll be visiting Ijen.