The Copper-Roof Palace is an 18th-century palace in Warsaw, Poland. It takes its unusual name from its copper roof ��� a rarity in the first half of the 18th century. The palace since 1989 is a branch of the Royal Castle Museum. The palace is contiguous with Warsaw's Royal Castle, and down a slope from the Castle Square and Old Town. Beneath the palace, a 17th-century lodge still exists.