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.
Day Boulevard, Boston, MA, 02127 map. Take I-93 to Exit 15. Make a left at the light to rotary, and onto Day Boulevard, follow the water to Castle Island. You'll find free beach parking along the street the entire way, and a free lot for Castle Island at the end of the road.