A hidden three-foot-wide house separates these two regal churches.

An early work of the architect Álvaro Siza Vieira, these swimming pools blend into the beach.

The oldest Roman lighthouse still in use.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

Historic medieval fortified city in southwest France.

Home to fantastic views and ancient graves.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

Hundreds of hidden passageways weave through the old quarters of Lyon.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

A relatively obscure antihero from the Marvel Comics universe adorns a wall inside Iceland's main airport.

This ancient theater was once the home of fierce gladiatorial battles.

Walk through living pictures and music in the Cathedral of Images.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

A marvel of Byzantine engineering under the streets of Istanbul.

The gravestone of the suffragist leader attracted extra visitors during the 2016 election.

An antique cemetery in New York, this land is home to any number of famed corpses.

The world’s largest truck stop includes a barber shop, chiropractor, and a huge museum with antique trucks.

Lined with plaques and tributes to veterans, this patriotic street was founded by Mexican immigrants.

The world's longest wildlife overpass provides Hilversum's critters with a safe alternative to trying their luck on the roadway.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

Rare recess caves fill this unbelievably beautiful Ohio park.