In 2008, Israeli billionaire Lev Leviev and his family moved into the most expensive private home ever built in the United Kingdom. Located in North London, the house cost $68 million USD (35 million British pounds) to build, and is home to one of the world's most expensive private pools [source: Cleland]. Leviev's indoor swimming pool in lined with gold tiles and has a full spa and sauna. When it's time to host a party, the pool has a retractable cover that transforms the area into an opulent ballroom. Unfortunately, this pool is open only to friends and family, so don't cancel your community pool membership just yet.