The Thousand Islands, like the Adirondacks, were once valued mainly as a hunting and fishing ground. In 1822, United States and Canadian authorities agreed on a boundary line through the island region that zigzags to avoid crossing any islands, leaving none owned in common by the two countries. In 1823, Elisha Camp bought the entire group from the United States, then divided and resold the islands. Demand remained limited until 1872, when George M. Pullman invited President Grant, General Sherman, their families, and friends to spend a week among the islands, drawing newspaper correspondents and visitors from across the country and helping create great demand for island property. In the early 1890's, New York City hotelier George Boldt visited the Thousand Islands, decided to build a summer home there as a gift and monument of love for his wife Louise, bought Hart Island from E. K. Hart, renamed it Heart Island, and altered its shape with the addition of Swan Pond and a small boat lagoon so that the island became heart shaped.