Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

One of only two commuter aerial tramways in the United States.

A natural gas leak provides a flickering flame beneath a waterfall.

An abandoned castle owned and ignored by Masons carries a cursed history.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

This volcanic cave lake is essentially hard proof that Iceland is the most magical place on Earth.

Outlaws, hot springs, and tragedy have all left their mark on this ancient road in the Icelandic highlands.

A stratovolcano located in the south of Iceland, with a long history of charted activity and a rich mythology attached.

This hobbit-y little hot spring may be the oldest spring used by humans in all of Iceland.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

This elegant arc of a waterfall marks a religious turning point.

Rising from the sea like a stone monster.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This dormant volcanic crater has been converted from a roiling pit of magma to a pleasant hiking spot.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

"Only the devil could play golf here."

Towering basalt columns, a creation of fire and ice.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Dramatic river bend surrounds a natural red-rocked pedestal.