7:  Four Fairfield Pond worth 250M USD

Located in New York, United States of America and built in 2003

6: The Odeon Tower Penthouse worth 330M USD

Located in Monaco and built in 2009-2015

5: Les Palais Bulles worth is 420M USD

Located in Cannes, France and built in 1975-1989

4:  Villa Les Cedres worth is 450M USD

Located in Saint-Jean-Cap-Ferrat, France and built in 1830

3:  Villa Leopoldas worth is 750M USD

Located in French Riviera, France and built in 1929 to 1931

2:  Antilia worth is 2000M USD

Located in Mumbai, India and built in 2006-2010

Buckingham Palace is Located in London, United Kingdom and built in 1705