These tombs were built into the side of a mountain so that ancient angels could reach the dead.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A marvel of Byzantine engineering under the streets of Istanbul.

An ancient iron pillar in Delhi that seems to be rustproof.

Picnic on the seashore in the footsteps of ancient kings, protected by giant mythical cat beasts.

This precariously balanced boulder is said to be a hunk of stolen butter dropped by the gods.

This ancient Hindu temple is covered in thousands of colorful statues and has a long mythological history.

The other side is actually green.

Finnish lake, and scene of an infamous murder mystery.

A former imperial sea-fortress and Soviet prison.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

The Guardian of Tallinn.

Sweden's oldest animated sign is still lighting up the skyline today.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The original goat tower, the one that started it all.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

At Chicago's revered Field Museum, visitors are invited to learn about and literally explore DNA.

Pizza with a side of fine art.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Home to a protest movement, a bombing, and a dramatic change in labor history.

A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.