Early Medieval stones sit on display at the beautiful Govan Old Church in Glasgow.

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

This large copper bolt represents the benchmark for measuring sea levels in most of Europe.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

A set of seven houses, each built in a style that represents a European country.

Europe's official "zero-level," the equator of elevation.

Amsterdam's former hotspot for public executions and dissections.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This unattributed sculpture in Amsterdam is hiding in plain sight.

A beautifully eclectic mix of architectural styles.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This colorful statue welcomes visitors to a Barcelona park.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This memorial, built by fascist dictator General Franco in 1960, has been repurposed by the people of Catalonia.

Stunning Roman aqueduct used for 1900 years and still standing.

Long tunnels run under the ancient chariot racing circuit to the tower.

This Roman arena once played host to bloody gladiatorial battles.

Touching the iron railings of Tarragona's balcony to the Mediterranean is said to bring good luck.