A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

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

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

A spectacular hidden beach in Ireland has the dark, disturbing nickname of "Murder Hole Beach."

You can see three Irish counties from this Neolithic hillside fort, once the seat of the Kingdom of Ailech.

The atmospheric road was never meant to be so creepy.

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

A trail of "Game of Thrones"-themed doors carved from fallen trees from the iconic Dark Hedges.

Northern Ireland's Brobdingnagian stepping stones.

This tiny train shuttles passengers to one of Northern Ireland's most spectacular sights.

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

The lake that fills and empties itself at random.

Amazing vistas await visitors to this stretch of coastline.

A harbor town pays tribute to a heroic wartime carrier pigeon.

This stone harbor was key to Carnlough's limestone industry.

This gnarled old tree supposedly sprouted from seeds kept in the pocket of a 16th-century Spanish sailor.

The last Victorian market in Belfast.

The statue honors a beloved bird that once roamed St. George's Market.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

This massive monument has been telling the time for 150 years—at a slight angle.

Belfast's namesake river still winds below the city center, hidden from sight.

A small plaque highlights the damage caused by German air raids during World War II.

A palatial former bank building now houses what may be the poshest art venue (and former Tesco) in Belfast.

The only monument to name all of the passengers and crew who died on the RMS Titanic.