It may not look like much compared to today's superyachts, but Christina O has had quite the past.

Once a WWII Canadian frigate, the boat was bought by Greek shipping magnate Aristotle Onassis shortly after the war and turned into what was then one of the most luxurious yachts on the water.

Over the next several decades the Christina O would host a who's who list of big names: Winston Churchill, Jack Kennedy, Frank Sinatra, Marilyn Monroe, Elizabeth Taylor, John Wayne, Greta Garbo and Bette Davis, to name a few.

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The yacht was also the site for the wedding reception for Prince Rainier of Monaco and U.S. movie star Grace Kelly in 1956, as well as the 1968 wedding of Onassis and former first lady Jackie Kennedy.

The boat is currently for sale for £21 million -- or $35 million.