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

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

Picturesque intersection of witchcraft and ancient Christianity.

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

A unique seaside cave where Aleister Crowley faked his own death.

Perhaps the most spectacular grotto along the Algarve coastline.

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

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

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

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Nicknamed the 'Chestergate Hotel,' the underground tunnel had beds, lights, and even flushing toilets.

A wooden statue of a mermaid commemorates one fisherman's generosity.

This Welsh dockyard was the site of the not-so-secret construction of the Millennium Falcon for the original Star Wars trilogy.

The ruins of this magnificent Scottish castle blend both Gothic and Renaissance architectural styles.

A series of stained glass artworks that depict images of the hit TV show.

One of the first canal boat-lift inclines ever created.

This water-powered cliffside railway is one of the steepest funiculars in the world.

Dedicated to preserving railway history from across Ireland.

One of Scotland's earliest hydroelectric power stations.

These courts are the only ones of their kind in the world, made for a unique ball game that dates back to the 1700s.

The seaside ruins of an ancient salt production facility.

This fantastic museum honors Gloucester waterway heritage.

Carved between 3500 and 1000 B.C., the distinctive carvings at this site are poorly understood.

A rare example of a Lowland broch.