Nature and culture are prime attractions of Indonesian tourism. The former can boast a unique combination of a tropical climate, a vast archipelago, and a long stretch of beaches, and the latter complement those with a rich cultural heritage reflecting Indonesia's dynamic history and ethnic diversity. Indonesia has a well-preserved natural ecosystem with rain forests that stretch over about 57% of Indonesia's land (225 million acres). Forests on Sumatra and Kalimantan are examples of popular destinations, such as the Orangutan wildlife reserve. Moreover, Indonesia has one of the world's longest coastlines, measuring . The ancient Borobudur and Prambanan temples, as well as Toraja and Bali with their traditional festivities, are some of the popular destinations for cultural tourism.