Boldt Castle, United States
Located on an island in the St. Lawrence River,
Boldt Castle was built as a monument to the love between the millionaire hotelier George C. Boldt (owner of the Waldorf Astoria Hotel in New York) and his wife, Louise. Three hundred carpenters, stonemasons, artists, and other workers started building this luxury estate featuring 120 rooms with tunnels, a medieval-style clock tower, manicured Italian gardens, and even a drawbridge. Four years after construction began, however, Boldt's beloved Louise died suddenly, and he halted all construction immediately, leaving the castle to the elements.