This monument is a stark reminder of the horrors of the Zanzibar slave trade.

Hidden under the thick tropical vegetation of a cemetery is the tomb of Columbo Sahib.

This medieval wine press is one of the oldest in Cyprus.

An unusual double-stelae obelisk with ancient and mysterious origins.

The oldest hydroelectric plant in Czechia is now a museum.

This grisly effigy displays an early Christian martyr who was skinned alive and beheaded.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

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

According to Hindu belief, this shallow island chain was created by a god with an army of monkeys.

Qshla Koya is an Ottoman fortress located on a hillock in the central quarter of Koya.

The largest pool at its elevation sits on top of one of the most expensive resorts in the world.

Singapore's landscaping project is home to 18 incredible Supertrees.

The busy transport hub is home to the tallest airport slide in the world.

This historic street in Quito is known for its seven stone crosses—and one presidential assassination.

A collection of old steam and diesel locomotives sitting in a fenced-off garden.

The remains of a 19th-century school and living quarters are perched atop a mountain surrounded by a thick tropical forest.

Chelsea's soldiers were given strict orders when crossing this historic bridge.

This amazing medieval fortress stands atop a promontory along the famous Cinque Terre.

Believed to be the remains of the lost Temple of Minerva, this nymphaeum has been known by its misnomer to this day.

A schooner, nicknamed "The Unsinkable," with a long history of survival in the Indian Ocean.

This 2,000-year-old Doric bridge is still open to pedestrian traffic to this day.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

This vestige of Seychelles’s colonial past now resides in a busy intersection and didn’t chime for its first 96 years.

This beautifully restored fortification kept the city safe for centuries.