Once the grandest synagogue in medieval Spain, it now stands as a memorial of the 15th-century Jewish exile.

The fragmented remains of a massive public bath connected to the city's water supply.

This Roman arena once played host to bloody gladiatorial battles.

A fortress off the West coast of Portugal that dates back to 1502.

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

Perhaps the most spectacular grotto along the Algarve coastline.

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

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

A former plague hospital turned medical museum.

This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

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

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Amsterdam's former hotspot for public executions and dissections.

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

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

While most bridges allow roads to pass over water, this one allows water to pass over a road.

The tallest mountain in mainland Netherlands isn't actually very tall.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

This heavily worn bas-relief was once an honored fertility symbol.

Take a leisurely walk through the park to find the seven giant troll sculptures hidden throughout the park.

One of Belgium's oldest hospitals saw patients from the 13th to 20th centuries before becoming a museum.

This gruesome biblical parade celebrates the one day a year that a bit of Jesus' blood turns to liquid.