First Avenue is a north-south thoroughfare on the East Side of the New York City borough of Manhattan, running from Houston Street northbound to 127th Street. At 125th Street, most traffic continues onto the Willis Avenue Bridge over the Harlem River, which continues into the Bronx. South of Houston Street, the roadway continues as Allen Street south to Division Street. Traffic on First Avenue runs northbound (uptown) only. History Like most of Manhattan's major north-south Avenues, First Avenue was proposed as part of the Commissioners' Plan of 1811 for Manhattan, which designated 12 broad north-south Avenues running the length of the island. The southern portions of the Avenue were cut and laid out shortly after the plan was adopted. The northern sections of the Avenue would be graded and cut through at various intervals throughout the 19th century as the northward development of the island demanded. The IRT Second Avenue Line ran above First Avenue from Houston Street to 23rd Street before turning west at 23rd and then north onto Second Avenue. This elevated line was torn down in 1942. First Avenue has carried one-way traffic since June 4, 1951. A protected bike lane was established along the left side of the avenue south of 50th Street in 2011. Description First Avenue passes through a variety of neighborhoods. Starting in the south at Houston Street, First Avenue passes through the East Village, once a predominantly German and Jewish neighborhood, now a gentrified area populated mostly by hipsters and yuppies. First Avenue then runs by two large urban development projects, Stuyvesant Town and Peter Cooper Village, two middle-income housing developments that sit on what used to be the Gashouse District, an industrial area. These fill the east side of the avenue from 14th to 23rd Streets. The avenue is very wide in this segment, and is separated by a median. The New York Veterans Affairs Medical Center, the Bellevue Hospital, and NYU Medical Center fill the blocks from there to 34th Street. Between 42nd and 47th streets, the avenue runs past United Nations Headquarters. Here a local bypass, United Nations Plaza, splits from the main road, which runs through the First Avenue Tunnel, rejoining the local street at 49th Street. Crossing under the Queensboro Bridge and entering the Upper East Side, First Avenue runs through a number of residential areas. It serves as one of the main shopping streets of the