In the early 20th Century, George C. Boldt, (millionaire owner of the famous world-class hotel, the Waldorf Astoria) began to build full-scale a castle on the Heart Island for his wife Louise. Three hundred workmen worked to build this six-storey, 120-room castle. No detail was overlooked, no cost spared. In 1904, his wife suddenly disappeared, and all the work was stopped. Boldt never returned to the island and left behind this monument witness of his love. The castle is currently owned by the Thousand Islands Bridge Commission, which is restoring the castle to all its splendor.