The Golden Square Mile owes much of its charm to its built heritage. Primarily developed from the 1850s to the 1930s, the original architectural style draws from an eclectic mix of Neo-classical, Neo-Gothic, Romanesque, Queen Anne, and even a bit of Art Nouveau. Some of these gems still stand today, many of which can be found on the McGill University campus or have been otherwise donated to public and private non-profit causes. Examples include the Allan Memorial Institute, formerly known as Ravenscrag, Thomson House, and the mansion built by jewelry tycoon John Henry Birks.