Ancient Bronze Age rampart that was used into the middle ages.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

This snug medieval lane is one of the narrowest streets in the world.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

One of the largest underground systems runs under Canada's largest urban center.

Europe's largest prehistoric mound – burial site of a legendary king?

The largest stone circle in the world has ended up bringing up more questions than it has answered.

The granddaddy of English geoglyphs dates back to the late Bronze Age.

Human-made caves excavated to hide a secret society of wealthy pagans.

See massive fossils that are over 200 million years old in northeastern Arizona.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

Dolphins, ancient clams and hundreds of waterfalls make this one of the world's top tourist destinations.

A glacier pocked with ice caves and surrounded by rainforests.

The glacier tucked within a New Zealand rainforest.

Major tourist destination known for its bubbling mud-pools and hot thermal springs.

The once and future home of New Zealand's famed Pink and White Terraces.