Owner: Lakshmi Mittal, worth $16.5 billion
Purchse Price: 57 million pounds in 2004 (nearly $90 million)
The Indian steel magnate picked up a 55,000-square foot mansion (not pictured) from billionaire Bernie Ecclestone and, after pouring millions more into its renovation, named it "Taj Mittal." Located on Billionaires Row, it has 12 bedrooms, a pool and marble sourced from the same quarry as the Taj Mahal.