One Shell Plaza (OSP) is a 50 floor skyscraper at 910 Louisiana Street in Downtown Houston, Texas, United States. At its completion in 1971, One Shell Plaza was the tallest building in Houston, Texas, standing 715 feet (218 m) tall. Including the antenna tower on its top, the height is 1,000 feet (304.8 m). One Shell Plaza was designed by Skidmore, Owings & Merrill LLP. Associate architects of One Shell Plaza were Wilson, Morris, Crain & Anderson, and the landscape architects were Sasaki Associates. Shell Oil Company, a subsidiary of Royal Dutch Shell, is headquartered in this building. The law firm Baker Botts is also headquartered there. The Plaza Club, on the 49th floor of the building, has dining, entertainment, and meeting facilities.