New York's commuter nightmare is bad, but the world's most crowded cities are even worse

A July 17 track fire at New York City's 145th St. station caused citywide delays for commuters, and it was just the latest in a recent string of subway failures.

Over the past several months, multiple delays have led to crowded platforms where hordes of sweaty bodies squeeze together. An overworked subway system is to blame.

The same is happening around the world, and on a far more concerning scale. By the year 2050, 70% of the world will live in cities, according to the Population Reference Bureau.

The most population-dense cities grapple with unique challenges. They fight for resources, like housing and personal space, and they put infrastructure to the test.

Here's just a taste of what life is like.