The filthiest national park in America hides an uneasy lesson about the future of cities

New York City is a giant, strange place.

Spread across four major landmasses and dozens of little islands, the metropolis is home to far more diverse natural landscapes than many people, including some of those who live there, may realize.

I recently visited one such place on a warm Sunday: Dead Horse Bay, which is probably the filthiest, nastiest, and weirdest national park in America.

Take a moment and turn that name over in your mouth: Dead Horse Bay.

Dead Horse Bay is home to the only beaches in New York City that lie vacant on a hot summer Sunday. Shattered glass saturates its sand so thoroughly that when waves crash in they tinkle like wind chimes. (Scroll down to hear that spooky noise.)

The Bay is part of Gateway National Recreation Area, which is a series of campsites, wetlands, and monuments scattered across eastern Brooklyn, Queens, and New Jersey and run by the National Park Service.

But it's hardly a normal place for a weekend excursion, and in the trash-filled waters lurk some uncomfortable lessons about the future of human civilization.

Here's what it's like there and what you need to know about it.