This area was once known for being a lawless haven for rough-and-tumble sailors, earning the maritime-themed nickname "the black sea."

One of the indelible moments of the American Revolution took place at this location.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.

A tiny plaque marks the location of the water source that facilitated the birth of modern-day Boston.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

American revolutionaries and British soldiers alike are buried here in the fourth-ever cemetery in Boston.

Statue commemorating the use of ether in anesthesia.

The Boston square dedicated to the dark poet who was born nearby.

A beacon atop a downtown building provides Bostonians with weather forecasts and baseball news.

This stone commemorates the island's launch into international aviation.

Under the desolate and windswept northern coast of Barbados stands a small oasis filled with sea anemones.

This historic black and white monastery is one of Bulgaria's architectural jewels.

An homage to the medieval rulers of Bulgaria.

An abandoned saucer-shaped monument in the Bulgarian mountains.

The remarkably well-preserved final resting place of a powerful ancient Thracian king.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

Ella Fitzgerald, opera singer Enrico Caruso, and dancer Isadora Duncan all performed in this lavish, supposedly haunted theater.

Huge stairway leads to this massive gallery.

A 19th-century relic of timekeeping.

In the middle of a forest you can find the first landing place of an air balloon in the Netherlands.

This small Spanish village is home to dozens of public paintings meant to trick the eye.

The tallest tower in Cáceres's Old Town.

A strange anthropomorphic stele with a mysterious inscription that has never been deciphered.