begun removing its tire reefs. The Ocean Conservancy now includes tire removal during the International Coastal Cleanup in September of each year. Erosion prevention Some artificial reefs are used to prevent coastal erosion. They can be designed to act in multiple ways. Some are designed to force waves to deposit their energy offshore rather than directly on the coastline. Other reefs are designed to hold sediment on beaches. These reefs trap the sediment. These reefs are custom-designed for each unique zone. Examples Florida Florida is the site of many artificial reefs, many created from deliberately sunken ships, including Coast Guard cutters Duane and Bibb and the U.S. Navy landing ship Spiegel Grove. Osborne Reef In the early 1970s, more than 2,000,000 used vehicle tires were dumped off the coast of Fort Lauderdale, Florida to form an artificial reef. However, the tires were not properly secured to the reef structures, and ocean currents broke them loose, sending them crashing into the developing reef and its natural neighbors. As of 2009, fewer than 100,000 of the tires had been removed after more than 10 years of efforts. Neptune Reef Neptune Memorial Reef was originally conceived as an art project called The Atlantis Reef Project and was envisioned and created by Gary Levine and Kim Brandell. Burial at sea became a way of financing the project. As of 2011, about 200 "placements" had occurred. Cremated remains are mixed with concrete and either encased in columns or molded into sea-star, brain-coral, castings of lions or other shapes before entering the water. Ex-USS Massachusetts In 1921 the US battleship was scuttled in shallow water off the coast of Pensacola, Florida and then used as a target for experimental artillery. In 1956 the ship was declared the property of the state of Florida by the Florida Supreme Court. Since 1993 the wreck has been a Florida Underwater Archaeological Preserve and is included in the National Register of Historic Places. She serves as an artificial reef and recreational dive site. Ex-USS Oriskany The world's largest artificial reef was created by sinking of the 44,000 ton aircraft carrier off the coast of Pensacola, Florida, in 2006. Ex-USNS Hoyt S. Vandenberg The second-largest artificial reef is USNS Hoyt S. Vandenberg, a former World War II era troop transport that served as a spacecraft-tracking ship after the war. The Vandenberg was scuttled seven miles off Key West on May 27,