Hiding the longest subterranean river known in the world.

Cross mysteriously appeared for 36 years.

A pilgrimage site where people ask Saint Dymphna to watch over those who are not of sound mind.

A Museum of Psychiatry in a still-operating mental institution.

A museum celebrating the Canadian forces that liberated Belgium from the Nazis replete with battlefield miniatures and multiple Gardens.

Home of the largest single-phase AC generator in the world.

The ancient tomb acts as a calendar that keeps perfect time.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A submerged village appears when dam levels drop.

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

Come stay at a live-in art installation.

Most powerful transmitter in Germany only broadcasts in the French language.

A cemetery with goat-horn bedecked gravestones.

Largest private bird collection in Iceland, formed from a tragic accident.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

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

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

The natural mummy of the less than chivalrous Knight Kahlbutz.

Cell phone tower constructed entirely of wood.

Swarms of dainty flying insects swarm into the Petaloudes Valley to get busy.

Two churches shoot bottle rockets at each others' bell towers in an unusual Easter celebration.

Pagan monument converted to Christianity with the population.

Fascinating early attempt at a Jewish autonomous settlement.

A small Portuguese cottage formed between boulders in the countryside.