L'elephant triomphal

In 1758, French architect Charles Ribart proposed an elephant-shaped structure to be erected on the site where the Arc de Triomphe now stands. Equipped with a kind of air conditioning and furniture that would fold up into the walls, the three-level structure would've had a drainage system built into the elephant's trunk.

Update: in comments Joseph Barbaccia points out a more contemporary cousin of Ribart's elephant — Lucy, a 124-year-old structure in Margate, New Jersey, dubbed "the world's largest elephant."