Central City/Black Hawk Historic District and funds as a result. Central City/Black Hawk Historic District The Central City/Black Hawk Historic District is a National Historic Landmark District that encompasses Central City and Black Hawk, Colorado. They are adjacent former gold mining camps in the Front Range of the Rocky Mountains in Gilpin County, Colorado, United States. For a time, the area was known as the Richest Square Mile on Earth. The district was designated a National Historic Landmark on July 4, 1961. On May 5, 1859, John H. Gregory discovered a rich deposit of gold in hard rock, the first such discovery in the Rocky
City of London Bridge, Tower Bridge and the Millennium Bridge. The City's flag flies over Tower Bridge, although neither footing is in the City. The size of the City was constrained by a defensive perimeter wall, known as London Wall, which was built by the Romans in the late 2nd century to protect their strategic port city. However the boundaries of the City of London no longer coincide with the old city wall, as the City expanded its jurisdiction slightly over time. During the medieval era, the City's jurisdiction expanded westwards, crossing the historic western border of the original settlement—the River Fleet—along Fleet