Between the mid-sixth and mid-fourth centuries B.C., Buddhism was founded in northeastern India and soon spread throughout the Asian subcontinent, influencing cultural and spiritual practices, art, and architecture. Today, around half a billion people around the world practice Buddhism, which is built upon principles like the Four Noble Truths and pursuit of nirvana. While traditional Buddhist temples often reflect the architectural styles of the region, all are designed to facilitate quiet reflection and meditation. (Here are 38 beautiful holy sites around the world.)