Indonesia is a country that remains surprisingly little known. Virtually everyone has heard of Bali, but few people realize that there are 17,507 other islands, which make up an archipelago 3,275 miles wide. (For context, it is 2,446 miles from New York to Los Angeles.) Indonesia is the world’s fourth-most-populous nation, with about 261 million inhabitants. And its biodiversity is second only to that of Brazil's. In the far east of the country, in the Papua province, there are still animist tribal groups, such as the Yali people, whose way of life has changed little since the Stone Age. In contrast, the country’s capital, Jakarta, is a vast sprawl of concrete high-rise buildings.