*m. Blackwell Island Lighthouse, New York - This 50-foot-tall, gray gneiss, Gothic-style lighthouse was built in 1872. It is not an official Coast Guard lighthouse. The lighthouse’s purpose was to “effectually light” the nearby New York City Insane Asylum for boats navigating the treacherous Hell Gate waters. It was designed by architect James Renwick, Jr., whose other works include Smallpox Hospital and St. Patrick’s Cathedral. Inmate labor was probably used in the city-run project..