Two ancient yew trees with a chapel and an altar built inside their hollow trunks.

Two small chapels housed inside an ancient tree.

The tomb of a hard traveling saint is constantly covered in shoes as offerings to heal disabled youth.

Rest stops along this pathway offer some of the best views of the Acropolis of Athens.

An underground tropical garden sits inside a Paris Métro Station.

The largest Commonwealth memorial to the missing and dead of the Battle of the Somme.

This Finnish town on the Arctic Circle is trademarked as the Official Hometown of Santa Claus.

A park that allows you to get up close and personal with one of the world's largest open volcanic craters.

View the ancient remains of buildings and the ancient "River of Hades" before hopping on a train.

Where commuters walk through remnants of an ancient Greek necropolis.

Gladiators once walked this ancient, subterranean passage.

A sharp sculpture made of thousands of pieces of jagged glass.

Legend says this sacred tree was a gift from goddess Athena.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

This cannonball has been lodged in the church wall since a 1695 bombardment destroyed the city center.

Towering high above the neighborhood of La Candelaria, the church is easily recognizable by its distinctive red-and-white striped facade.

Colombia's first concrete structure doubles as a replica of Versaille's Petit Trianon Belvedere and a symbol for development.

Every Sunday, Bogotá turns 75 miles of its city streets into a bicycle superhighway.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.

This Bogotá museum houses the world's largest collection of pre-Columbian gold relics.

The celebrated eyesore created by starry-eyed sweethearts.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.