Located near the National Mall, the Smithsonian Institution Building was completed in 1855. Designed by James Renwick, Jr., the red Seneca sandstone edifice features a faux Norman architectural style that incorporates late-Romanesque and early-Gothic details. Although slaves were not used in the construction, they were used to quarry the stone. Colloquially known as the Smithsonian Castle, the building initially held the institution’s entire collection of art and other objects. Designated a National Landmark in 1965, its Victorian arched windows, dark woodwork and terrazzo floor evokes the serene ambiance of a house of worship. The 4.2-acre Enid Haupt Garden is situated adjacent to the Castle.