The Citygate Ecotower is a proposed supertall skyscraper designed for London, United Kingdom as a proposal by M3 Architects. It was designed to be an environmentally friendly building and would be clad in photovoltaic cells and have wind turbines on the roof. The location of the tower would be over a large transport interchange (Aldgate High Street).
At 500 floors, 1,500 metres (4,921 ft) high it would be the tallest building in Europe and possibly the world. It would have a mixed use of offices, hotel and apartments.