The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

An ancient octagonal weather station named for the eight Greek gods of wind.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This may be the last of London's wooden pavements, which were once a common sight in the city.

At this cozy bar tucked down a hidden Galway backroad, Guinness makes the Gaelic come out.

This open-air mosaic gallery honoring an English artist took hundreds of volunteers more than seven years to create.

Several cannonballs of mysterious origins decorate two buildings in Stortoget's main square.

This grave marks one of few bodies retrieved from the disastrous Franklin Arctic expedition.

The only surviving piece of Copenhagen's 16th-century defensive wall.

The art museum is decorated with creatively remodeled pre-Nazi swastikas.

This ordinary street was made infamous by a legendary visit from the devil.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

This sublime architectural marvel is a rare example of an expressionist church.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Walk through a restaurant's refrigerator door to reach this hidden bar.

Nikola Tesla's former home contains an homage hidden from plain sight.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

Colloquially known as “piss alley,” this narrow street filled with tiny bars and barbecue stands looks like it was pulled straight out of “Blade Runner.”

This hill nestled in the Scottish lowlands was a ritual site for over 4,000 years.

The shop where the girl who inspired the beloved character once bought sweets is now a book-themed commercial curiosity.

This cemetery overlooking the Benbulben rock formation is the final resting place of one of Ireland's most beloved poets.

Silverware in the sidewalk outside a grocery store cements this neighborhood’s Italian culinary history.