Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Macabre astrological automaton clock dating to the late 1400s.

Monument to a suicide protesting the Soviet invasion.

Op-art architecture designed for happiness.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Baroque celebration of the end of the Great Plague of Vienna.

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

Designed as a reminder of one of the darkest moments in Austrian history.

The final resting place for the remains of 143 Habsburg royalty.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

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.

Inside this small chapel tucked away in the forest is one of the most well-preserved Danse Macabre frescos.

Longest fortress system anywhere in Europe.

An ethereal glowing blue ocean cave in Croatia.

Legend has it fairies gathered at the site of this medieval castle.

This beautiful Croatian fortress is haunted by legends of forbidden love.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

This modern, multimedia museum takes visitors on an evolutionary journey back in time.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

The attic of a four-century-old canal house hides a clandestine church.