A relic of Victorian grandeur hides beneath a busy South London road.

An ornate private entrance to the Vienna subway built specifically for the emperor.

The world's largest private telescope collection hides in a secret wing of a Dutch auto museum.

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.”

Get in line for Lisbon’s most famous sandwich.

One of the smallest bookstores on the planet.

The devil-defying mark left by a saint as a boy is visible inside Lisbon's cathedral.

In the Monastery of São Vicente resides a gallery devoted to a breathtaking collection of seashells.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This giant sculpture made of trash is a critique of society's wastefulness.

This historic streetcar system has been running since the 19th-century.

When this former hospital pharmacy closed in 2013 it already looked like a museum, so they turned it into one.

The original version of Porto's most famous sandwich is just as good here as it was a century ago.

Building owners can take out tiles for free at this repository for historic building materials.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

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

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

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

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

Elaborate tile work in this railway station tells the story of Portugal.

Dedicated to one of the author's most iconic works.