algae bloom wiped out the sponge fields in the Gulf of Mexico, causing many of the sponge boats and divers to switch to shrimping for their livelihood, while others left the business. Eventually, the sponges recovered, allowing for a smaller but consistent sponge industry today. In the 1980s, the sponge business experienced a boom due to a sponge disease that killed the Mediterranean sponges. Today there is still a small active sponge industry. In 2007 and 2008, the City of Tarpon Springs established Sister City relationships with Kalymnos, Halki, Symi, Hydra, and Larnaca, Cyprus, honoring the close historical link with these Greek-speaking islands. Historic sites There are several districts or properties in Tarpon Springs that have been listed on the National Register of Historic Places: Tarpon Springs Greektown Historic District Tarpon Springs Historic District Arcade Hotel Old Tarpon Springs City Hall Old Tarpon Springs High School Safford House Rose Hill Cemetery Tarpon Springs Depot Many sites related to the sponge industry within the Greektown District also have been recognized. They include but are not limited to two sponge packing houses: E.R. Meres Sponge Packing House N.G. Arfaras Sponge Packing House And several boats: N.K. Symi (Sponge Diving Boat) St. Nicholas III (Sponge Diving Boat) St. Nicholas VI (Sponge Diving Boat) Geography According to the United States Census Bureau, the city of Tarpon Springs has a total area of , of which is land and (45.83%) is water. Climate Tarpon Springs' climate borders on humid subtropical and tropical savanna, with warm temperatures year-round, although winter nights are cool. Annual precipitation is around . Winters are warm, with daytime highs of to , and nightly lows of to . Freezing temperatures ( or lower) occur infrequently, while snowfall is extremely rare; there was accumulation in 1977 and 1989, while the years 1899, 1954, 1958, 1973, 2001, 2006, 2010, and 2014 either saw light snow mixed with rain, or flurries. The record low temperature of was observed on four different dates: December 1, 1962, December 13, 1962, December 14, 1962, and January 13, 1985. Summers are hot and very humid, causing frequent afternoon thunderstorms that can occasionally produce hail, and, even tornadoes or waterspouts off the Gulf of Mexico. Daytime temperatures usually range from to , with temperatures over very rare. The record high temperature of was observed on July 10, 1997. Spring and fall are generally warm. Demographics As of the census