Its primary edifice, a white marble Neo-Classical structure built in 1903, is located at 18 Broad Street. However, an adjacent annex, built in 1922, is situated at 11 Wall Street, and another subsidiary structure is located at 20 Broad Street. The New York Stock Exchange is located at 15 Water Street. A modern skyscraper has been proposed as a replacement. In general, the financial district is made up of long lines of tall buildings with names like Goldman Sachs on Wall Street or Merrill Lynch on Madison Avenue. These are where the investment banks are located. Between them are large office blocks that house the accounting firms, lawyers, insurance companies, and other businesses involved in the finance industry. The southern part of the district is called Manhattanville and is home to Columbia University. It used to be a rural village until after the Revolutionary War when it became a destination for new immigrants looking for farmland. Today, it is one of the most expensive neighborhoods in New York City. The northern part of the district is called Battery Park City and was developed after World War II by the federal government to help revitalize downtown Manhattan. It's a popular spot with tourists who want to see the Statue of Liberty and 9/11 memorial. Although not really part of Downtown, Central Park is located right in the middle of the district.