505, previously known as 505 CST and Paramount, is a residential skyscraper currently under construction in downtown Nashville, Tennessee, located at the intersection of Fifth Avenue and Church Street. 505 will stand on the location originally intended for the cancelled Signature Tower. The 45-story building will be 543 feet tall and feature 403,000 sq ft of floor space, making it the second tallest building in Nashville, behind the AT&T Building.