No, the New York City Subway was not the first in the world; it was actually a latecomer compared to European systems. The world's first underground railway was the Metropolitan Railway in London, which opened on January 10, 1863. It used steam locomotives in brick-lined tunnels, which made the air quite smoky for early passengers. The first city in the United States to open a subway was actually Boston in 1897 (the Tremont Street Subway). The New York City Subway did not open its first line until October 27, 1904, over 40 years after London. However, New York eventually became the largest and most famous system due to its 24/7 operation and the massive scale of its four-track express system. Other early systems include the Budapest Metro (1896), which was the first on the European mainland and the first to be fully electrified, and the Paris Métro (1900). While New York didn't start the trend, it perfected the "mass" in mass transit, moving more people through a larger number of stations than almost any other system in the Western world.