Location: Robins Island, New Suffolk, New York (Peconic Bay)
Purchased: $11 million*
Current Value: $20.5 million*

Wall Street guru Louis Moore Bacon made his millions from investing and working the stock market. Bacon bought Robins Island in the 1990s for just $11 million at the time ($20.49 million in today’s money), but Robins Island isn’t a Bahamian paradise like we’ve seen elsewhere on this list.

Instead, the 453-acre island is located off the coast of New Suffolk in New York. Situated in the Peconic Bay, Bacon, a billionaire tycoon who closed his hedge fund a couple of years ago, has kept the island’s natural beauty preserved. It isn’t accessible to the public, and the only information on the forested escape lies in satellite photos.