A spectacular Petrine Baroque summer palace commissioned for Catherine I by Peter the Great.

A unique sculpture calls the outside of this steakhouse home.

Walk along the medieval fortifications that have been protecting Tallinn since the 14th century.

A medieval setting reimagined into a unique art alley.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

This former power station is now a museum dedicated to the region's coal-producing history.

Devastated landscape used for hundreds of years by the Romans as their primary mining site.

This 19th-century prison once held Irish revolutionary Constance Markievicz, writer Frank O’Connor, and a nine-year-old pickpocket.

A freedman baker’s lavish tomb has a relief showing various stages of Roman bread making.

The first statue to be added to Saint Peter's Square in over 350 years is an ode to migrants and refugees around the world.

This is the oldest Roman-made bridge in the city still existing in its original state.

A massive marble foot is tucked away in a small alley near the Pantheon.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

Plaques on its facade commemorate the Tiber's most destructive deluges.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

One could not be blamed for literally walking all over this supposed landmark.

A letterbox installed specifically for the first editor of the Oxford English Dictionary.

Dedicated to the European Sinti and Roma peoples murdered during the Holocaust.

One of downtown Berlin's last reminders of its Communist past.

This 135-year-old weather station studied the effects of the climate on human health.

One of the world's largest collections of pharmaceutical artifacts.

This artistic fountain display pays homage to this area's theatrical history.