Phra Pathommachedi or Phra Pathom Chedi (Thai: พระปฐมเจดีย์) is a stupa in Thailand. At 120.5 metres (395 ft) it is the tallest stupa in the world. The stupa is located in the Wat Phra Pathommachedi Ratcha Wora Maha Wihan (Thai: วัดพระปฐมเจดีย์ราชวรมหาวิหาร), a temple in the town center of Nakhon Pathom, Thailand.The name Phra Pathommachedi means the first holy stupa, given by Mongkut.