During the whaling era, wealthy Boston sea captains and merchant traders often created estates on Martha's Vineyard with their trading profits. Today, the Vineyard has become one of the Northeast's most prominent summer havens and has attracted numerous celebrity regulars. Vineyard Sound is the stretch of the Atlantic Ocean that separates the Elizabeth Islands and the southwestern part of Cape Cod from Martha's Vineyard. To the west, it joins Rhode Island Sound, and on its eastern end it connects to Nantucket Sound. The Elizabeth Islands number eight and have a total land area of 13.34 square miles. All of them except Cuttyhunk and Penikese are privately owned by the Forbes family, while Cuttyhunk and Penikese are publicly accessible. Woods Hole Passage separates the Elizabeth Islands from the town of Woods Hole on the mainland. It is a naturally occurring rocky and sometimes treacherous passage, with a current often running strong between Buzzards Bay and Vineyard Sound. The village of Woods Hole is home to a world renowned center for marine, biomedical, and environmental scientific exploration.