Ancient catacombs form the foundation for this Rococo orgy of a church.

The stunning interior of this Gothic church is covered in ornate gold details.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

One of the smallest bookstores on the planet.

This charming candle shop has been in business since 1789.

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The best place in the world to buy tinned fish.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

Originally meant to hold a statue of King William IV, this support sat empty for years. Today, it hosts a rotating cast of public artwork.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

Metro station with a claim to rock n' roll fame.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

Cold war icon and onetime "hole" in the iron curtain.

Dedicated to the European Sinti and Roma peoples murdered during the Holocaust.

One of the world's heaviest musical instruments towers within a popular urban park.

At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

A fascinating insight into daily life in the Eastern Bloc.