A 6th-century stone lies at the site of the mythical battle waged between King Arthur and his nemesis Mordred.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

This historic pub has maintained much of its 1906 decor, including a small sequestered room for women, where orders were slipped through a tiny window.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This cheese shop also houses a museum devoted to Dutch dairy.

Originally built to monitor fishing, this Victorian tower now educates visitors about the local salmon industry.

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 ruins of an 800-year-old monastery boasts the tallest round tower in Ireland.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

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

A remarkably intact castle that once was the largest in Ireland.

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

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

An 80-year-old plane tree is devouring an iron bench at Ireland's oldest law school.

One of Ireland's most infamous prisons for rebels including men, women and children.

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

Horrifically creative torture devices and shame punishments line the walls of this chilling museum.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

An abandoned train station in Munich constructed for the 1972 Olympic games.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Residing along a busy thoroughfare, this sculpture urges passersby to consider the future.