Tour CB21, formerly Tour Gan, is an office skyscraper located in La Défense, the high-rise business district situated west of Paris, France. It was designed by celebrated American architect Max Abramovitz. Built from 1972 to 1974, the tower is 179 m (587 ft) tall at roof height. However, it reaches 187 m (614 ft) once including the antenna located on the roof. It was the second tallest building in Paris upon its completion. Its ground shape is in the form of a Greek cross. In 1972, during construction, a protest campaign opposed the building of Tour Gan. Protesters demanded a reduction in height. However, the tower was completed at the planned height. Today, the main tenants are Suez Environnement and AIG France. The structure is owned by Fonciere des Regions.