One of Ireland's lesser-known megalithic structures.

When the tide is high, you can see the Atlantic pushing up through a deep, jagged hole in the rock.

Ireland's most northerly island is hauntingly beautiful. Its lighthouse was the last glimpse of home for many Irish emigrants bound for the U.S.

At the time of its construction, this hydroelectric power plant was the largest in the world.

The ruins of a sixth-century monastery sit on the banks of the River Shannon.

A gated cross stands on the site where an Irish revolutionary met his end.

A diminutive, thousand-year-old church believed to be the smallest in Ireland.

The ruins of a monastery that dates to the 7th century.

This rare and ancient Christian relic is one of Ireland’s oldest freestanding stone crosses.

The remains of a 13th-century Franciscan friary have survived multiple attempts at destruction, most recently in 1921.

The largest stone circle in Ireland.

It's said this geological anomaly was caused when the Devil took a bite out of the Irish mountainside.

The remains of a majestic house that was once stood in the crosshairs of the Irish Republican Army.

Ancient Bronze Age rampart that was used into the middle ages.

These moss-covered medieval ruins tower atop the smallest of Ireland's Aran Islands.

A mysterious Neolithic tomb is perched along the edge of a modern golf course.

A stunning medieval castle owned and restored by the famed actor Jeremy Irons.

Fantastic stainless steel dragon gates complete with mesh wings.

Impressive mining ruins overlook a spectacular view of Ireland's Copper Coast.

An ancient holy well said to be used by the patron saint of sailors and travelers, lost in the boggy west of Valentia Island.

A Neolithic passage tomb said to have sheltered two legendary Irish lovers.

This 14th century tower house was once the home of Irish poet W.B. Yeats.

This Neolithic passage tomb forms part of a World Heritage Site.

Behemoth, cannon-like telescope operated by generations of Irish earls.