The list is topped by Buckingham Palace worth over $1.5 billion. But the palace is not completely private property. Meanwhile, Indian business magnate Mukesh Ambani build a skyscraper in Mumbai, India, that is worth $1 billion and is the richest private house in the worth. The Ambani family moved into the 27 story house in 2012. Know all the Top 10 Richest Houses In the World below.