These lesser-known Maltese catacombs date back over 1,700 years.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

A seaside castle complex that stood through centuries of conquests.

The quiet field that inspired one of the most famous songs of all time.

What do we know about the real woman behind one of the Beatles' most famous songs?

This subterranean studio is filled with fascinating kinetic art.

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

An incarceration museum on the spot of possibly the oldest prison in England.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

There is beauty and history in the ruins of this former company town.

A tribute to the life and work of the beloved "Peanuts" cartoonist.

This memorial plaque remembers a strangely shallow maritime disaster known as "Chicago's Titanic."

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

A much-maligned monument to teetotalism.

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

A moving memorial to the fallen and missing from WWI trenches.

This memorial museum chronicles the apocalyptic destruction of the First World War.

The oldest known metal-mining site in England dates back to the Bronze Age.

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 enchanting archway is the only surviving portal into Dublin's lost medieval wall.

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

The house where the writer spent his formative years.