In an ongoing series, BBC News focuses on aspects of life in countries and cities around the world.
What may seem ordinary and familiar to the people who live there, can be surprising to those who do not.
Millions of people depend on the New York City Subway each day to get to and from work.
Each line has its own unique character and most New Yorkers have their favourites and their not-so-favourites.
Perhaps the most historic journey is on the A-train, which is also the longest ride. Matt Wells hopped on board.