A walk through the historic city center, under the streets of Seattle.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A giant Troll lurks under one of Seattle's oldest bridges.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A crumbling hospital from the 1850s on Roosevelt Island.

World's first "penitentiary," meant to be humane, drove men insane.