This Beaux-Arts masterpiece (1911) by Carrère and Hastings contains some of the most spectacular interiors in the city, as well as one of the largest research collections in the world. The two marble lions—nicknamed Patience and Fortitude— that flank the exterior grand staircase serve as the institution's mascots. An information desk in Astor Hall offers floor plans and information about the day's events (readings, lectures, performances). Major exhibitions are held in Gottesman Hall; you can also visit the richly paneled DeWitt Wallace Periodical Room, with its 13 murals by Richard Haas.