Vitamin D -- specifically the form D3 -- is the only vitamin your body makes itself. It's fat-soluble, which means your body stores vitamin D in its adipose tissue -- in its fat. And, if you want to be specific about things, this vitamin is actually a hormone.
Sullivan's Castle Island, South Boston, MA, Est. 1951. Castle Island. Located at the end of Carson Beach, on Pleasure Bay in South Boston, Castle Island is a 22-acre recreation site, and the site of Fort Independence. Castle Island was really an island until several land reclamations through the years extended causeways and eventually roadways.
About an hour's drive north of Boston, the Massachusetts seacoast's other cape, Cape Ann, is actually an island (map), separated from the rest of Massachusetts by the Annisquam River, a short salt water channel between Gloucester harbor and Ipswich Bay.