Boston Harbor. Boston Harbor is a natural harbor and estuary of Massachusetts Bay, located adjacent to Boston Massachusetts. Artists like Fitz Henry Lane and Childe Hassam captured its maritime beauty and bustling activity, often highlighting the harbor's role in trade and naval history. Lane's luminous landscapes showcase the tranquil waters and ships, while Hassam's impressionist works depict the vibrancy of the harbor scene. It is home to the Port of Boston, a major shipping facility in the Northeastern United States. The Brig Antelope in Boston Harbor, by Fitz Henry Lane, 1863 Since its discovery to Europeans by John Smith in 1614, Boston Harbor has been an important port in American history. Early on, it was recognized by Europeans as one of the finest natural harbors in the world due to its depth and natural defense from the Atlantic as a result of the many islands that dot the harbor. It was also favored due to its access to the Charles River, Neponset River and Mystic River which made travel from the harbor deeper into Massachusetts far easier. It was the site of the Boston Tea Party in 1773, as well as almost continuous building of wharves, piers, and new filled land into the harbor until the 19th century. By 1660, almost all imports came to the greater Boston area and the New England coast through the waters of Boston Harbor. A rapid influx of people transformed Boston into an exploding city. The health of the harbor quickly deteriorated as the population of Boston increased. As early as the late 19th century Boston citizens were advised not to swim in any portion of the Harbor. In the 19th century, two of the first steam sewage stations were built. With these mandates, the harbor was seeing small improvements, but raw sewage was still continuously pumped into the harbor. In 1919, the Metropolitan District Commission was created to oversee and regulate the quality of harbor water. However, not much improvement was seen and general public awareness of the poor quality of water was very low. In 1972, the Clean Water Act was passed in order to help promote increased national water quality. Signage on the streets of Boston Since the mid-1970s organizations within the Boston community have battled for a cleaner Boston Harbor. More recently, the harbor was the site of the $4.5 billion Boston Harbor Project. Failures at the Nut Island sewage treatment plant in Quincy and the companion Deer Island plant adjacent to Winthrop had far-reaching environmental and political effects. Fecal coliform bacteria levels forced frequent swimming prohibitions along the harbor beaches and the Charles River for many years. The city of Quincy sued the Metropolitan District Commission and the separate Boston Water and Sewer Commission in 1982, charging that unchecked systemic pollution of the city's waterfront contributed to the problem. That suit was followed by one by Conservation Law Foundation and finally by the United States government, resulting in the landmark court-ordered cleanup of Boston Harbor. The Charles, Mystic, and Neponset rivers empty into Boston Harbor.