structure, the road providing a hardened crest for the dike, slowing erosion in the event of an overflow. It also provides access for maintenance as well perhaps, as a public service. Examples Notable causeways include those that connect Singapore and Malaysia (the Johor-Singapore Causeway), Bahrain and Saudi Arabia (25-km long King Fahd Causeway) and Venice to the mainland, all of which carry roadways and railways. In the Netherlands there are a number of prominent dikes which also double as causeways, including the Afsluitdijk, Brouwersdam, and Markerwaarddijk. In the Republic of Panama a causeway connects the islands of Perico, Flamenco, and Naos to Panama City on the mainland. It also serves as a breakwater for ships entering the Panama Canal. Causeways are also common in Florida, where low bridges may connect several man-made islands, often with a much higher bridge (or part of a single bridge) in the middle so that taller boats may pass underneath safely. Causeways are most often used to connect the barrier islands with the mainland. In the case of the Courtney Campbell Causeway, however, the mainland (Hillsborough County) is connected by a causeway to a peninsula (Pinellas County). The Churchill Barriers in Orkney are some of the most notable sets of causeways in Europe. Constructed in waters up to 18 metres deep, the four barriers link five islands on the eastern side of the natural harbour at Scapa Flow. They were built during World War II as military defences for the harbour, on the orders of Winston Churchill. The Estrada do Istmo connecting the islands of Taipa and Coloane in Macau was initially built as a causeway. The sea on both sides of the causeway then became shallower as a result of silting, and mangroves began to conquer the area. Later, land reclamation took place on both sides of the road and the area has subsequently been named Cotai and become home to several casino complexes. Specific causeways around the world Various causeways in the world: Adam's Bridge, historic causeway which existed till 1480 CE Afsluitdijk, Netherlands. Canso Causeway, Nova Scotia, Canada () Churchill Barriers, 4 causeways in Orkney, scotland Colaba Causeway, Mumbai, India Courtney Campbell Causeway, Tampa Bay, Florida, United States Gaoji Causeway, Xiamen, China Hindenburgdamm, 11km rail link between the island of Sylt and the German mainland () Johor–Singapore Causeway () King Fahd Causeway, Bahrain, Saudi Arabia () Lake Cuitzeo Causeway, Michoacán, Mexico (19.9380°N