Due to the thousands of immigrants flooding the streets each year, New York City, by the mid-1800s, was one of the most crowded places on earth. In March of 1888, a blizzard paralyzed the city and became the catalyst for a new development in public transportation: an underground rail system. After years of political jousting and planning, construction began in 1900. Four years later, the Interborough Rapid Transit (IRT) opened to the public. American Experience: New York Underground chronicles the building of this monumental project that forever changed urban dwelling. Through archival photographs, transcripts, and contemporary newspaper accounts, this documentary illustrates the dedication, manpower, and ambition it took to build the 21-mile route. Hundreds of accidents occurred, thousands of workers were injured or disabled, and at least 44 people lost their lives.