This strange sculpture of a menacing skull surrounded by sun rays was discovered at the foot of the Pyramid of the Sun.

One of the largest Buddhist stupas in the world keeps an eye out in every direction.

A Himalayan monastery claims to have a piece of a centuries-old abominable snowman.

Last stop before the top of the highest peak in the world.

Jumping-off point for a climb up Mt. Everest is the most dangerous airport in the world.

A network of ancient Egyptian tombs built into the cliff face along the Nile.

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

These sacred Mesoamerican ruins feature peculiar petroglyphs hidden in the stones.

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

The singular ruins of a mysterious lost city.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

This colossal ancient jaguar sculpture was used as a vessel for the hearts torn from sacrificial victims.

Located near Cairo's El Korba district, the abandoned mansion continues to inspire mystery and rumor throughout the city.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

Central America's deepest lake is actually a volcanic caldera, surrounded by three volcanoes.

One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

These spectacular, symbolic serpents lie within the shadow of the Great Temple.

These enigmatic columns tower over the ruins of an ancient Toltec city.

Gladiators battle and chariots race daily in the ruins of a once-great Roman city.

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

The ruins of an ancient temple to the Aztec wind god discovered in the middle of a metro station.

The most southerly spot on New Zealand's South Island is home to surreally shaped, permanently mangled trees.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.