Hundreds of notes give thanks to the patron saint of lost causes.

Gliwice Radio Tower, likely the tallest wooden structure in the world.

This antique thermometer honors the creator of the first universal temperature scale.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

Climb inside an iron crystal magnified 165 billion times its normal size.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

Northern Ireland's Brobdingnagian stepping stones.

These barriers stand as stark reminders of Northern Ireland's troubled past.

This tiny train shuttles passengers to one of Northern Ireland's most spectacular sights.

These murals stand as reminders to the troubled history of this Northern Ireland city.

This historic funicular system combines the old with the new while offering delightful views over the surrounding valley.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

A 13th-century convent where St. Margaret of Hungary spent her teenage years.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Breathtaking and huge 430 year old maps of Italy.

Historic funicular railway, believed to be the shortest railroad in the world.

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

The topiary maze at the Habsburg hunting lodge.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.