Shanghai Tower is the world's third-tallest structure behind a building that reached its full height in which year ?
Shanghai Tower:  It is the world's second-tallest building by height to architectural top (behind Dubai's Burj Khalifa, 828 m) and the world's third-tallest structure (behind Tokyo Skytree, 634 m). Tokyo Skytree:  It became the tallest structure in Japan in 2010 and reached its full height of 634.0 m in March 2011, making it the tallest tower in the world, displacing the Canton Tower, and the second tallest structure in the world after the Burj Khalifa (829.8 m/2,722 ft).
2011