Hinduism is the world’s oldest religion, according to many scholars, with roots and customs dating back more than 4,000 years. Today, with about 900 million followers, Hinduism is the third-largest religion behind Christianity and Islam. Roughly 95 percent of the world’s Hindus live in India. Because the religion has no specific founder, it’s difficult to trace its origins and history. Hinduism is unique in that it’s not a single religion but a compilation of many traditions and philosophies.