It is believed that our waters hold the remains of vessels sunk during the Seminole Indian wars, the American Civil War, the Spanish-American War, the period of prohibition, and both World Wars. However, those that do bear some artifacts are exciting and valuable windows to our past. Huge coral-encrusted chunks of ballast can still be seen at Looe Key where the H.M.S. Loo went down in 1774. The site of the 1733 sinking of the San Pedro, too, is marked by little more than centuries-old ballast. Others, like the Avanti that sunk in 1907, are marked by their rusting metal frames that provide hiding spots for jewfish and lobster.
Historic lighthouses are another part of our nautical heritage.
There are currently 16 lighthouses marking the reef tract, three of which are listed in the National Register of Historic Places. In 1825 construction was begun in a number of locations to warn vessels of the hazards that lay just below the surface. Over the years time and storm damage have taken their toll on these important structures. There is some evidence, though, that these waters may be preserving even older artifacts. Sinkholes that are common to limestone areas have been found to contain some of the earliest records of humans in North America.