The Three Sisters are three rocky islands in the Potomac River in Washington, D.C., west of the Key Bridge. A notable landmark in colonial times, the islets are less well known as the Three Sisters Islands and Three Sisters Island. Bridges have been proposed for the Three Sisters several times, most recently in the 1960s, when the Three Sisters Bridge proposal led to a decade of protests and ultimately, its cancellation. Geographical description The Three Sisters are part of the Fall Line, a geologic feature which distinguishes the sedimentary coastal plain of the mid-Atlantic region of the United States from the basement rock of the inland. Part of this basement rock, the Three Sisters are composed of granite. Roughly 300,000 years ago, Atlantic Ocean levels were much higher. At that time, the lower Potomac River was submerged beneath the Atlantic Ocean, whose shores reached the Three Sisters. The Potomac River near Washington, D.C. averages deep, except near shore or the Three Sisters. However, there is a deep channel near the Three Sisters that is generally about deep, but can drop to just or less during low tide or periods of little precipitation. The rock formation generates sand bars which are often visible at low tide. No grass grows on the sandbars near Three Sisters. They are fully submerged at high tide. The height of the sandbars wax and wane according to floods, spring silt runoff, and drought. The (traditional) navigational high water mark is Georgetown, which is why the town came to be. Georgetown, which preceded the establishment of the District of Columbia, was the furthest point inland that shipping vessels could reliably reach when coming up from the Atlantic Ocean. The C&O Canal was proposed as a means of navigating inland beyond Georgetown and past the obstructions of Little Falls and Great Falls. Legends and history Various legends and historical oral tales are associated with the Three Sisters. One of the earliest stories involves three Algonquian sisters who crossed the river in an attempt to win the release of their brothers, who had been kidnapped by another tribe. They drowned while crossing the river, and were turned into the rocky islets. A less commonly cited legend says three daughters of the local Native American chief were marooned on the islands by their father after rejecting the husbands he picked out for them. The legend holds that the sisters cursed