At the time of its completion, it was the tallest dam in the world.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

An architect's childhood fantasy treehouse made real.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

This stunning concert hall has become a symbol of Iceland's national recovery.

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

An encyclopedic collection of mammal penises.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.