populous city in the world in 1925, overtaking London, which had reigned for a century. Manhattan's majority white ethnic group declined from 98.7% in 1900 to 58.3% by 1990. On March 25, 1911, the Triangle Shirtwaist Factory fire in Greenwich Village killed 146 garment workers. The disaster eventually led to overhauls of the city's fire department, building codes, and workplace regulations. The period between the World Wars saw the election of reformist mayor Fiorello La Guardia and the fall of Tammany Hall after 80 years of political dominance. As the city's demographics stabilized, labor unionization brought new protections and affluence to the working class, the city's government and infrastructure underwent a dramatic overhaul under La Guardia. Despite the Great Depression, some of the world's tallest skyscrapers were completed in Manhattan during the 1930s, including numerous Art Deco masterpieces that are still part of the city's skyline, most notably the Empire State Building, the Chrysler Building, and the 30 Rockefeller Plaza. Returning World War II veterans created a postwar economic boom, which led to the development of huge housing developments targeted at returning veterans, the largest being Peter Cooper Village-Stuyvesant Town, which opened in 1947. In 1951–1952, the United Nations relocated to a new headquarters the East Side of Manhattan. The Stonewall riots were a series of spontaneous, violent protests by members of the gay community against a police raid that took place in the early morning hours of June 28, 1969, at the Stonewall Inn in the Greenwich Village neighborhood of Lower Manhattan. They are widely considered to constitute the single most important event leading to the gay liberation movement and the modern fight for LGBT rights. In the 1970s, job losses due to industrial restructuring caused New York City, including Manhattan, to suffer from economic problems and rising crime rates. While a resurgence in the financial industry greatly improved the city's economic health in the 1980s, New York's crime rate continued to increase through the decade and into the beginning of the 1990s. The 1980s saw a rebirth of Wall Street, and Manhattan reclaimed its role at the center of the worldwide financial industry. The 1980s also saw Manhattan at the heart of the AIDS crisis, with Greenwich Village at its epicenter. The organizations Gay Men's Health Crisis (GMHC) and AIDS Coalition to Unleash Power (ACT UP) were founded to advocate on behalf of those stricken with the disease.