Diego Rivera hid various people and symbols in his first large-scale mural project.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

A marvel of Byzantine engineering under the streets of Istanbul.

Tucked in the back of this amazing antique store is an important piece of medical history.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Museum dedicated to the terror regimes of Hungary.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

An artist's mausoleum with a haunting echo.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

Home to three historic ships from the age of Vikings.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

The house that took a plunge into the facade of a museum.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Op-art architecture designed for happiness.

The beautiful baroque library of the Hapsburg empire.

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

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

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

Once the home of a hermetic monk, this cave now houses a small church.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

A Hungarian pharmacy museum with a box full of mummy powder.