Cincinnati Union Terminal opened in March 1933 and unified the city's rail travel, which had previously operated from five separate passenger terminals. Built when rail travel was already declining, it ceased operating as a passenger railroad station in 1972. The terminal reached full use only during World War II, when as many as 34,000 people passed through the building daily in 1944. In preservation efforts, 14 mosaics by Winold Reiss depicting Cincinnati industry of the 1930s were saved from the concourse and moved to the Greater Cincinnati Airport. The restored terminal became a Museum Center in November 1990 with the opening of the renovated Cincinnati Museum of Natural History and the new Cincinnati History Museum. It is regarded as one of the nation's most outstanding Art Deco train stations and was listed on the National Register of Historic Places in 1972.