Ratchadaphisek Road, also known as Bangkok Inner Ring Road is a major road in Bangkok, Thailand. Conceived in 1971 and opened in 1976, it connects earlier portions including Asok Montri, Wong Sawang and Charan Sanitwong Roads to form the city's inner ring road system. The road's name comes from the celebration 25th year of a monarch's reign of King Bhumibol Adulyadej.