The Eiffel tower is about to get an extension to it's top floor courtesy of Serero Architects. According to their site....
Serero Architects unveils its design for the extension of the Eiffel Tower top floor. The project will extend the top floor plate of the tower by grafting a high performance carbon Kevlar structure on it. The structure will be temporarily bolted to the slab without requiring any modification of the existing structure. It will expand the usable floor area from 280 m2 to 580m2.