peninsula in southeastern Newfoundland, Canada; it is joined to the main part of the island by a 4-mi- (6-km-) wide isthmus between Placentia and Trinity bays and extends for about 110 mi with a maximum width of 60 mi. Its high point is about 1,000 ft (300 m) on the Atlantic coast south of St. John's, and it is deeply indented by Conception Bay (north) and St. Mary's Bay (south). Probably first visited in 1497 by the navigator John Cabot, the peninsula was named after the Arthurian Isle of Avalon by Sir George Calvert (later Lord Baltimore), who obtained a charter for a part of it in 1623. In 1866 the first successful transatlantic cable was landed at Heart's Content on Trinity Bay, and in 1941, on board a ship anchored in Placentia Bay off Argentia, the Atlantic Charter was signed by Franklin D. Roosevelt and Sir Winston Churchill.