other coastal barriers around the shorelines of the borough and the metropolitan area to minimize the risk of destructive consequences from another such event in the future. Around 15 percent of the borough is considered to be in flood-risk zones. On October 31, 2017, a terrorist took a rental pickup truck and deliberately drove down a bike path alongside the West Side Highway in Lower Manhattan, killing eight people and injuring a dozen others before crashing into a school bus. Geography Components The borough consists of Manhattan Island, Marble Hill, and several small islands, including Randalls Island and Wards Island, and Roosevelt Island in the East River, and Governors Island and Liberty Island to the south in New York Harbor. According to the United States Census Bureau, New York County has a total area of , of which is land and (32%) is water. The northern segment of Upper Manhattan represents a geographic panhandle. Manhattan Island is in area, long and wide, at its widest (near 14th Street). Icebergs are often compared in size to the area of Manhattan. Manhattan Island Manhattan Island is loosely divided into Downtown (Lower Manhattan), Midtown (Midtown Manhattan), and Uptown (Upper Manhattan), with Fifth Avenue dividing Manhattan lengthwise into its East Side and West Side. Manhattan Island is bounded by the Hudson River to the west and the East River to the east. To the north, the Harlem River divides Manhattan Island from the Bronx and the mainland United States. Early in the 19th century, landfill was used to expand Lower Manhattan from the natural Hudson shoreline at Greenwich Street to West Street. When building the World Trade Center in 1968, 1.2 million cubic yards (917,000 m3) of material was excavated from the site. Rather than dumping the spoil at sea or in landfills, the fill material was used to expand the Manhattan shoreline across West Street, creating Battery Park City. The result was a 700-foot (210-m) extension into the river, running six blocks or , covering , providing a riverfront esplanade and over of parks; Hudson River Park was subsequently opened in stages beginning in 1998. Little Island opened on the Hudson River in May 2021, connected to the western termini of 13th and 14th Streets by footbridges. Marble Hill One neighborhood of New York County, Marble Hill, is contiguous with the U.S. mainland. Marble Hill at one time was part of Manhattan Island,