[V]egetation disguises one of the most important, and least appreciated, cultural history sites in the country, archaeologists say. Much of Fig Island was built by man, not nature. Three of the four separate pieces of high ground that make up the 40-acre island were constructed about 4,000 years ago. Oyster shells - with some conch-type shells, broken pottery and a few animal bones mixed in - were crafted into stadium-like rings and crescents for reasons that remain a mystery... The Fig Island complex features one ring with the largest open interior plaza (slightly more than an acre), another ring with...