Mexico City's metro is clean, quiet, and efficient. Jeffrey Greenberg/UIG via Getty Images

Mexico City is one of the largest metropolitan areas in the world, and its metro carries 1.6 billion people every year.

New York City is the only subway that carries more passengers, but Mexico City's system puts it to shame.

My experience in the Mexican capital showed that trains can be fast, clean, and quiet, without the need for expensive station upgrades or even express trains.

New York City could learn a lot from Mexico City's metro system.

The Mexican capital is the largest city in North America, and even the US' largest city pales in comparison to its sweeping neighborhoods and suburbs that stretch for miles across the valley.

Despite carrying 1.6 billion passengers per year - second only to New York in North America - in and around Mexico's capital, which is the largest Spanish speaking city in the world, the system is relatively simple to navigate and eerily quiet compared with New York's screeching trains (and, often time, loud musicians).

And while the streets above are clogged with traffic and pollution, below ground, trains were quiet, quick, and efficient. Here's what my experience was like: