The reigning monarch of the Principality of Monaco, Prince Albert II has an estimated net worth of $1 billion, according to Forbes. Prince Albert II is the ruler of the Principality of Monaco and Head of the House of Grimaldi. He is the son of Prince Rainier III and Hollywood darling Grace Kelly, succeeding his father in April 2005, although he had assisted in conducting Stare affairs since 1984. In June 2010 he announced his engagement to former South African Olympian Charlene Wittstock, marrying across two days between the 1st and 2nd July 2011. He inherited his enormous family fortune after his father’s death including real estate, art, antique and classic cars and a stake in the Monte Carlo casino.