Biggest property in the US: Ira Rennert’s Mansion

The property, which began construction in 1998 and completed in 2003 was so large that the local community thought that it was going to be used as a hotel, business retreat or religious centre.

The mansion is estimated to be worth between $170m -$180m and comes in at number 2 on the list of the world's top 5 most expensive houses.