This elegant structure, completed in 1788, once sheltered exotic trees in winter. It now houses a gallery featuring an impressive selection of sculpture collected from across Europe by King Stanisław August Poniatowski. The highlight is the beautifully restored Kamsetzer Colonnade in which copies of ancient sculptures stand against background paintings of an idyllic Italian landscape.
Also here is the Royal Theatre, an 18th-century auditorium featuring beautiful stucco and trompe l'oeil decoration, which is still used for regular performances.