Indian steel tycoon Lakshmi Mittal calls this Kensington Palace Gardens home his "Taj Mittal." He bought it for £57 million, about $89.4 million in today's dollars. The property is on the tree-lined "Billionaires' Row," where other highly affluent people like Roman Abramovich and Leonard Blavatnik also own property. It has 55,000 square feet of space, 12 bedrooms, a Turkish bath, swimming pool, picture gallery and ballroom.