This lake in northwest Iran has started turning from green to red more frequently than scientists are comfortable with.

Modern-day cave dwellers carve elaborate homes out of volcanic debris.

The palace of the King of Kings, burned by Alexander the Great.

This ancient fortress in Iran was once the oldest and largest treasury in the world.

Legend says if this neo-Gothic basilica is ever officially completed, the world will come to an end.

The gondolas let you glimpse a bird's-eye view of one of the world's highest capital cities.

This huge green space packed with activities will make you forget you're in the middle of the Ecuadorian capital.

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

The world's tallest aluminum statue is also the world's tallest image of a winged Virgin Mary.

Founded as a refugee camp, now a popular tourist spot.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

Mosaics, storks, and brothels—this ancient city has it all.

Classical ruins that remember ancient Rome's presence in Africa.

This dizzying span over the ancient Algerian city was once the highest suspension bridge in the world.

A century-old stone hermitage overlooks this remote pass in the Hoggar mountains, surrounded by a landscape of eroded volcanic cores.

The abstract sandstone rock formations at this Algerian national park are rich with prehistoric art.

An alien landscape of chalk-rock in the Egyptian desert.

Three wildly colorful calderas top this otherworldly volcano chain.

The unique design was created by the traditional way communal rice paddies were divided among the indigenous people.

Where cemeteries are carved into the side of cliffs and infants are buried in the hollows of trees.

The unique funeral practices of the Toraja can be seen here with graves carved into caves and hung off cliffs.

One man and his wife have turned a barren Korean island into a fantastical botanical wonderland.

Malaysia's floating mosque.

Known as the leaning temple, the sacred structure has somehow developed a severe nine-degree slant.