The medieval ferry service has been going strong since the 14th century.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This huge metal monument is slowly being stripped to its concrete skeleton.

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

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

Where the lovelorn find a home for their sentimental keepsakes.

Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

Controversially restored in the 1970s, this giant 15th-century mosque is shrouded in legend.

Where Stoddart and Connolly suffered in the infamous Bug Pit.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Ancient barriers wrap around what was once an important stop along the Silk Road.

An underground world of gorgeous, palatial metro stations designed as a nuclear shelter complex.

Prowl through this sprawling bazaar under a massive Soviet-era dome for delicious eats.

Once a luxurious flagship of the Soviet Union, this Brutalist structure remains a landmark of Tashkent’s communist past.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

This former Imperial summer home was the venue for a royal slap that once echoed 'round the world.

Legend says if you stick your thumb in the hole and it gets wet, your wish will be granted.

One of the most colorful free outdoor attractions in San Diego, this park is filled with murals and ties to history.

A life-sized imperial army, buried in battle formation, has stood underground for over 2,000 years—built not for war, but for eternity.

A ruined hilltop watch base in the Aravalli ridge above Jaipur, where broken fort walls and a forgotten lookout overlook Man Sagar Lake, reachable only by scrambling through cactus-covered desert trails.

This charming, flower-filled, paved cul-de-sac is filled with artists' studio-houses built in the 1920s.