Europe's oldest still-operational tea farm also boasts a spectacular view.

An underground magnet for ever-changing street art.

Unruly residents were housed in this one-person cell until the Black Maria arrived.

Named for a Greek oracle that interpreted the words of Zeus, this beautifully-restored manor home was once home to the architect of the Marshall Plan.

True to its name, this little house presents like a dollhouse, and surprising details are revealed with a quick peek through the window.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

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

One of few vertical lava tubes in the world accessible by foot.

These unusual rooms on wheels are holdovers from the 1960s.

Perhaps the most spectacular grotto along the Algarve coastline.

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

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

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

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

The world's oldest bookshop still in operation.

Ancient paintings known as the "Sistine Chapel of Cave Art."

A fitting attraction for the corn capital of the world.

The highest point in Washington state is a volcano covered in glaciers.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

This fairy-tale, neo-Gothic church in the Azores is a world of magical realism.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

Puffin enthusiasts flock to Europe's largest seabird cliff, which over one million birds call home.