Built in the 19th century, Alcatraz Federal Prison was the strongest and nearly escape proof prison in America. There were a total of 336 cells but never in its operating history was a full house. These inmate cells were 5 feet by 7 feet and fully isolated from the world. The strong winds, heavy fog, cold water and strong waves surrounding the entire island made it the most secured and the most feared place for highly dangerous prisoners. The prison was shut down in the late 1900s due to high operational costs. Since shutting down, the Island is maintained by the National Park Services who offer day and night tours of the island.