Casa Loma – Toronto, Canada

Atlas Obscura: Sir Henry Mill Pellatt, a Canadian soldier and financier, gained immense wealth from founding the Toronto Electric Light Company in 1883, which brought electricity to the streetlights of Canada’s largest city. Business boomed – soon he was the chairman of 21 companies, owned railroads, generated electricity from Niagara Falls, and was knighted for his military service.  

I've visited here, and if you've seen the X-Men movies, you've seen the exterior and some of the interior.