North Bergen, New Jersey and Selkirk Yard in Selkirk, New York. The Hudson is crossed at numerous points by bridges, tunnels, and ferries. The width of the Lower Hudson River required major feats of engineering to cross; the results are today visible in the George Washington Bridge and the 1955 Tappan Zee Bridge (replaced by the New Tappan Zee Bridge) as well as the Lincoln and Holland Tunnels and the PATH and Pennsylvania Railroad tubes. The George Washington Bridge, which carries multiple highways, connects Fort Lee, New Jersey to the Washington Heights neighborhood of Upper Manhattan, and is the world's busiest motor vehicle bridge. The new Tappan Zee Bridge is the longest in New York, although the Verrazzano-Narrows Bridge has a larger main span. The Troy Union Bridge between Waterford and Troy was the first bridge over the Hudson; built in 1804 and destroyed in 1909; its replacement, the Troy–Waterford Bridge, was built in 1909. The Rensselaer and Saratoga Railroad was chartered in 1832 and opened in 1835, including the Green Island Bridge, the second bridge over the Hudson south of the Federal Dam. Pollution The Hudson River's sediments contain a significant array of pollutants, accumulated over decades from industrial waste discharges, sewage treatment plants, and urban runoff. Water quality in the river has greatly improved since implementation of the 1972 Clean Water Act (CWA). A 2020 report on the health of the river states that "Water quality in the Hudson River Estuary has improved dramatically since 1972 and has remained largely stable in recent years." Ecological health trends, such as in tributaries and wetlands, are varied in condition. The concentrations of toxic pollutants in fish and crabs are lower compared to measurements taken in previous decades, but fishing restrictions and health warnings remain in effect. The most significant pollution of the Hudson River was contamination of the river by General Electric (GE) with polychlorinated biphenyls (PCBs) between 1947 and 1977. These chemicals caused a range of harmful effects to wildlife and people who ate fish from the river. Other kinds of pollution, including mercury contamination and discharges of partially-treated sewage, have also caused ecological problems in the river. In response to the widespread contamination of the river, activists protested in various ways. A group of fishermen formed an organization in 1966 that would later become Riverkeeper, the first member of the Waterkeeper Alliance. Musician Pete Seeger founded the Hudson