Boldt Castle, New York

A huge Gilded Age summer house on an island in the Thousand Islands region of the St. Lawrence River. George Boldt was a hotel magnate, and started this project in 1900, though he stopped in 1904 when his wife died, and never finished it. It sat mostly abandoned for 70 years, before being purchased by the Thousand Islands Bridge Authority in 1977, for one dollar. The arrangement was to charge admission to visit it, and turn the proceeds over to restoration projects (to restore the partially finished building to its state before it became a vandalized ruin). The Authority still manages and maintains it, and has raised more than $15 million over the years, and has built more than was there originally.