There's a labyrinth of manmade tunnels stretching for over an acre beneath Bristol.

This pedestrian footbridge honors Pero Jones, an enslaved African who lived in Bristol.

This Grade II Listed Building with an Art Nouveau façade once contained a unique print shop.

The enigmatic skull gazes out over the ruins of a once-great Mayan city.

After becoming locally extinct, this esteemed avian now flies free in the forests around the ancient ruins.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

One of Ireland's best-preserved chambered cairns can be found next to a wishing tree.

One of Ireland's lesser-known megalithic structures.

The largest stone circle in Ireland.

The symbolic center of Ireland, this summit also offers panoramic views of the countryside.

A strange egg in a mucky bog of western Ireland marks the spot of an aviation milestone.

On the Irish coast, 18 members of the Howard family are eternally resting in an Egyptian pyramid.

A hugely vast Irish landscape of barren rock that stretches for miles.

This 5,300-year-old tomb with mysterious carvings crowns an Irish mountain.

The home of Ireland's last leprechauns is officially protected by the European Union.

A sacred well steeped in Pagan roots on the West Coast of Ireland.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This cemetery overlooking the Benbulben rock formation is the final resting place of one of Ireland's most beloved poets.

This 30-foot pile of rocks may be the grave of a mythological Irish queen.

Artifacts of whaling, with both its perils and adventure, are housed in this museum in a former candle factory.

Half-hidden by grassy slopes, this striking Spanish colonial fort is now a museum of underwater archaeology.

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

A monument in the shape of the mighty conch honors the history and symbolism behind this shell.