This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

Every equinox this Maya pyramid puts on a spooky ancient light show.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

Still standing despite its considerable slant, this tilted lighthouse has become a local symbol of resilience.

In a busy Oaxaca market, a nearly century-old drinks stand still serves family recipes from giant clay pots.

It's believed this golden brick is part of the legendary lost Aztec treasure.

The unique collection often goes unnoticed by visitors focused only on the archaeological objects.

This scenic cable car ride glides 100 feet above Mexico City.

Dating back to the second century, vestiges of prehispanic mural paintings are found in this underground palace.

This pre-Hispanic apartment complex also includes ancestral paintings that point to its military past.

This striking, two-toned confluence of rivers is visible from space.

A beautiful opera house in the heart of Amazonia has recently restarted performances after a 90-year hiatus.

An impressive site containing some of the earth’s rarest living fossils.

Ships still use this historic lighthouse to navigate dangerous, island waters.

For many years, the river that Julius Caesar led his army across into Italy was lost until re-identified.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

The San Marino-Rimini railroad was short-lived but this tunnel once provided shelter for hundreds of refugees during World War II.

Where members of the Crossbow Corps of San Marino demonstrate their skills.

The oldest civic library in Italy can trace its foundation back to 1619.

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

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.