One of the largest ossuaries in Spain is packed from floor to ceiling with bones.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

This tiny river island switches sovereignty every six months as part of a rare, centuries-old agreement.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

A hidden three-foot-wide house separates these two regal churches.

This giant sculpture made of trash is a critique of society's wastefulness.

This roadside shrine to an unofficial saint has welcomed the wishes and prayers of local believers for generations.

This now abandoned restaurant provides some of the most amazing views of Lisboa.

For more than two centuries, the canopy of this venerable tree has been a haven for songbirds and lovers.

This crumbling Portuguese ruin overlooks the populace it once ruled.

This house's itty bitty size means no humans allowed.

This "flat geyser" bubbles up out of the ground periodically like a disappearing river.

The largest prehistoric cemetery on the Balearic Islands dates back over 2,500 years.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

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

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

In Portugal, a secluded stretch of untouched natural beauty hides at the bottom of a steep hill.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

This small chapel is built of human bones and decorated with a golden skeleton.