Some time last week, the estate of Peter D. Williamson sold the late car collector's prized 1936 Bugatti 57SC Atlantic to the Mullin Automotive Museum in Oxnard, Calif., for between $30 million and $40 million, according to a person familiar with the transaction. Any figure in that range would make the Williamson Atlantic -- a heartbreaking piece of European automotive sculpture considered to be the epitome of French-Deco styling -- the most valuable car known to have changed hands.

The most valuable car ever sold at a public auction was a 1957 Ferrari 250 Testa Rossa, which sold for $12.2 million in May 2009.