Northern Ireland's Brobdingnagian stepping stones.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

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

This single room has survived the centuries with almost no deterioration.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

A statue in the center of Dublin dedicated to one of their favorite sons of rock & roll.

The modern birthplace of Irish freedom.

The oldest public library in Ireland.

A sculpture outside London's oldest cathedral honors the Mohegan chief who died while petitioning the king.

A particularly disconcerting tribute to Irish martyrs.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

This replica of the Greek structure is in the heart of Nashville.

Mysterious stone tower featured in many alternative histories of the New World.

A former poultry store that looks like a giant duck and is one of the "seven wonders" of Long Island.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Stroll through a wonderland of stupendous moss-covered trees.

A Civil War Museum with some notable medical antiques.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.