Chapultepec has the rather dubious distinction of being the only castle within North America to ever house actual sovereigns. It was originally constructed in 1725 on the orders of the Viceroy Bernardo de Gálvez, and was meant to be a large manor house for the Viceroy, who was the commander-in-chief of the Spanish colony, New Spain.
Currently the castle is the seat of National Museum of Cultures, which was formerly known as the Museum of Natural History. It was established as such by Lázaro Cárdenas in 1939. In this capacity it is open to visitors who can come and tour both the castle itself and the various collections it now houses. Through the past decades it has become a favorite location of movie directors appearing in both Robert Aldrich’s Vera Cruz and Baz Luhrmann’s Romeo and Juliet.
https://www.atlasobscura.com/places/chapultepec-castle