Antilia — $2 billion Residence (Mumbai)

Antilia, Mukesh Ambani's Mumbai residence, is the world's most expensive home at $2 billion. This 27-floor, 400,000 sq ft tower requires a staff of 600, with six parking levels, three helipads, and a ballroom designed to withstand a magnitude 8 earthquake. Its price is 28 times more than the $71.2 million spent on #4, The Pink Star Diamond. Designed by Perkins & Will, the structure uses 12,000 tons of steel and energy-efficient systems. The cost per square foot of $5,000 is 10 times higher than Mumbai's average luxury apartment.