This precursor to Modernism took off in Europe in the 1920s. But Howe's design was still considered unconventional in the U.S. when construction began. The building wasn't fully appreciated as a masterpiece until the height of the Modernism movement almost a decade after it was built. In 1939, the Philadelphia Chapter of the American Institute of Architects awarded it a gold medal. Thirty years later, the building was named "Building of the Century" by the same chapter.
Howe certainly didn't skimp on the materials used in the construction. The tower is covered with limestone, and the base of the building is faced with granite. A Cartier-designed clock greets visitors when they step off the escalator on the second floor. Other materials include stainless steel, Belgian black and Bardiglio gray marble, terrazo and exotic woods.
The Philadelphia Saving Fund Society closed in 1992, and the building sat unused for a few years. But the opening of the Pennsylvania Convention Center a block away in 1994 created a need for hotel space in the area, and in 1997, the Loews Corporation purchased the building, One of my favorite architectural details is the typeface used in the building's signage. It looks like ITC Avant Garde Gothic or Avenir, but it isn't. (Anyone know?)
Here's a great NY Times article about the PSFS renovation for those who want to learn more.