In 1898, the modern City of New York was formed with the consolidation of Brooklyn (until then a separate city), the County of New York (which then included parts of the Bronx), the County of Richmond, and the western portion of the County of Queens. The opening of the subway in 1904, first built as separate private systems, helped bind the new city together. Throughout the first half of the 20th century, the city became a world center for industry, commerce, and communication.