The Tokyo Skytree (Tōkyō Sukaitsurī) became the tallest building in Japan when it opened in 2012 and is the second-tallest building in the world after the Burj Khalifa. Stretching 634 m (2,080 ft) into the sky, the tower contains two observation decks, one at 350 m (1,148 ft) up and the other at 450 m (1,476 ft), from which you can see all the way to Mount Fuji during good weather! Lines on the day can get long, so book skip-the-line tickets in advance for the best experience.