Roman ruins top white travertine terraces formed by ancient hot springs.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

Hidden just under the waters around this Turkish island are the ruins of a once great city.

A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.

Roman ruins, natural methane fires and a lovely beach.

Sofia's legislative center is continuously reinventing itself.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

Pompeii's less famous neighbor is still revealing her secrets.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

A museum marks and documents the site of the Titanic's launch.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

Northern Ireland's Brobdingnagian stepping stones.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The final resting place of the great navigator, or maybe his brother.