In the midst of a city still mourning the losses suffered with the collapse of the World Trade Center, the opening of the American Folk Art Museum is a cause for rejoicing. The first major building completed since September 11, the structure is receiving enthusiastic architectural reviews. Critics are already pronouncing it one of the 16 greatest architectural sites in the city. Architectural critic Martin Filler calls it "not only New York's greatest museum since Frank Lloyd Wright's Guggenheim was completed in 1959, but nothing less than the city's best work of architecture since then—period."