Solomon R. Guggenheim Museum

The Guggenheim Museum on Fifth Avenue is one of the most significant architectural achievements of the 20th century. Wright's design features a continuous spiral ramp that allows visitors to take an elevator to the top and walk down through the galleries — a radical inversion of the conventional museum sequence. The building's organic, flowing form stands in dramatic contrast to the rectilinear grid of Manhattan. Wright worked on the design for 16 years before it was finally completed in October 1959, six months after his death. It is a UNESCO World Heritage Site.