The fairy tale castle of the "fairy-tale king."

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

Largest Roman Catholic church in North America.

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

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

The subtle science of a master molecular gastronomist.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

The quintessential Japanese rock garden has existed for more than 500 years.

Op-art architecture designed for happiness.

The final resting place for the remains of 143 Habsburg royalty.

A miniature city, once ruled by the Queen of the Netherlands.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Berlin's old airport.

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

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

The modern birthplace of Irish freedom.

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

A miniature village mimics the surrounding buildings so well it includes itself.

World's largest college campus includes a wildlife sanctuary and a former movie set on more than 28,000 acres.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

Last residence of H.P. Lovecraft featured in his story "The Haunter of the Dark."