The building on the left (known as 1 WTC) is built on the site of the original 6 WTC. At 541m it is the 4 tallest skyscraper in the world by pinnacle height. The building on the right (known as 2 WTC) is still under construction on the site of the original 5 WTC. This building is shorter than 1 WTC but will be the 3rd tallest building in NY. more progressed than the right building. Both buildings will be lower in height than the Twin Towers.