With its 6,000 inhabited islands, Indonesia is the world’s fourth most populous country, having approximately 270 million people and the largest Muslim population. The regional histories, religions, and lifestyles of the archipelago’s 300-plus ethnic groups are deeply reflected in their art and culture.Since ancient times, Indonesia’s indigenous people have believed in nature spirits and regularly perform rituals to worship mountains, trees, rivers, and animal-people. Stemming from this belief is the art of Balinese mask making, which is still alive today. Over time, elements of Hinduism and other belief systems have been integrated into this art form. With their dramatic colors and designs representing the spirits of various deities or ancestors, Balinese masks are considered sacred. The most common masks represent the characters of Barong and Rangda (or Durga), who always appear hand in hand in ritual dance.In many parts of Indonesia, the tribal or village dances can be traced back to prehistoric times. These include dances for healing, praying for good weather and a good harvest, fending off misfortune, or other purposes. The Hudoq is a traditional mask dance performed by the indigenous Dayak people of East Kalimantan province during the harvest festival from September to October. The Topeng dance is another mask dance popular in Java and Bali, and is performed for different purposes, such as storytelling, worship, or entertainment. At first, the themes of the dance centered around nature and ancestor worship. Later adventure stories about kings and heroes, such as the legendary tales of the Javan Prince Panji, were included, and Hindu epics such as the Ramayana and Mahabharata. Manuscripts of the Panji tales at selected libraries were inscribed in the UNESCO Memory of the World Register in 2017, signifying its importance to both Indonesian and world literature.