Happy Birthday, New York City Subway! - CityLab

Just a year after the formation of the City of Lake Worth, the New York City subway began operation. Its existence and continued transformation, expansion, led to the ever-changing New York City that we know today. The system allowed a density and intensity of development that still astounds today, but somehow it all seems to work. Click title for link to a story heralding the anniversary. Here's a bit and an interesting video from the time.

By the end of the 19th century, New York City's Lower East Side housed overhalf a million people per square mile. With vermin-infested tenements and rampant disease due to bad sanitation, “Staying clean in a neighborhood filled with horse stables, brothels, slaughterhouses and saloons was impossible,”writes transit historian Doug Most. Also difficult: Commuting to work to another neighborhood by horse.
New York needed to move and breathe. In 1894, the city signed the Rapid Transit Act into law, and began planning its first line, boasting to constituents that they'd be able to travel "from City Hall to Harlem in 15 minutes."
The time estimate may have been a bit of a stretch, but the city kept its promise of a better transit system. On October 27, 1904, the Interborough Rapid Transit Company debuted nine miles running through 28 stations to the public. For five cents a ride, travelers could skip from City Hall in lower Manhattan to Grand Central Terminal in midtown, head west along 42nd Street to Times Square, or hop north all the way to 145th Street and Broadway in Harlem.