The Hidden Melodies of Subways Around the World - The New York Times

When train doors close, these jingles warn riders to stand clear.

Inside the graffiti-covered 191st Street tunnel, NYC's deepest subway and only underground 'street

Ghost stations: abandoned subways around the world

Eight Works of Art Hiding in New York City, Travel

Canal Street station (IND Eighth Avenue Line) - Wikipedia

Clean, On Time and Rat-Free: 9 International Transit Systems With Lessons for New York - The New York Times

Trying to Live a Day Without Plastic - The New York Times

Riding public transit in Los Angeles can be scary. Here are some things I've seen - Los Angeles Times

Top 10 facts about subway systems

Underground: Subway Systems Around the World: by Kim, Uijung

MTA official defends 2nd Avenue Subway's $6B price tag

This subway line is the best-kept secret in NYC

The Case for the Subway - The New York Times

Explore NYC's Old City Hall Subway Station On This Tour

For South Korea's Senior Subway Riders, the Joy Is in the Journey - The New York Times

Crime, Anxiety, and the Story of the New York City Subway