Louvre Pyramid interior, Louvre Museum, Paris

According to Wikipedia:

The pyramid and the underground lobby beneath it were created because of a series of problems with the Louvre’s original main entrance, which could no longer handle an enormous number of visitors on an everyday basis. Visitors entering through the pyramid descend into the spacious lobby then re-ascend into the main Louvre buildings. Several other museums have duplicated this concept, most notably the Museum of Science and Industry in Chicago.