St. Nicholas Boat Line, one of Florida's oldest surviving attractions, was named after the patron saint of seafarers. For over 100 years, it has provided an informative cruise that includes an exhibition of hard-hat diving from the Sponge Docks down the Anclote River. Captain Michael J. Billiris started the business as an economic strategy because weather prevented many divers and crewmen from working during the winter months when tourists visited. Eventually, demand was so great that Michael, his sons, and his brother, Captain Theodore J. Billiris, operated five boats for rides down the Anclote River or deep-sea fishing forays. The St. Nicholas III was one of the sponge boats selected by the State of Florida to represent the sponge trade at the 1933 World's Fair in Chicago. During World War II, the Billiris family offered boats and supplies to U.S. Navy patrols in the Gulf of Mexico. Later, St. Nicholas boats were featured in films such as 16 Fathoms Deep (1948) and Beneath the 12-Mile Reef (1953), popular television shows, and numerous publications, including National Geographic. Although listed on the National Register in 1990, St. Nicholas III and IV are no longer extant.