This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

This short bridge is the only thing connecting a tiny Irish island to the mainland.

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.

The oldest inn in Kilkenny was established by the first convicted witch in Ireland.

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

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

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 modern birthplace of Irish freedom.

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

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

Museum devoted to the artificial language of Esperanto.

Handsomely crafted representations of our round planet.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

Baroque celebration of the end of the Great Plague of Vienna.

The beautiful baroque library of the Hapsburg empire.

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

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Museum dedicated to the terror regimes of Hungary.