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

These steeply terraced ruins are a stop along the Inca Trail to Machu Picchu.

These towering spires and glowing walls are carefully crafted from hundreds of thousands of icicles.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

This beautiful, historic church looks like something out of a simpler past.

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

A modest reminder of treacherous waters at the Golden Gate.

A winding path built in secret on the edge of the continent.

A 300-ship graveyard, with a few still visible at low tide.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The 1920s child prodigy author was last seen here at her Brookline home before vanishing at age 25.

Trinkets and toys lovingly handmade by maximum security prisoners.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

San Francisco's newly reopened hands-on science museum.

An vast warehouse of everyday treasures in Berkeley, CA.

The first bridge observation tower in the U.S. offers one of the best views of Maine.

This 19th century granite fortification is one of the most well preserved forts in New England.

This steep cable railway has been hoisting passengers in the heart of Québec City for over a century.