Neglected resting place of some of the city's early luminaries—and a woman encased in concrete.

Now a museum, this building was once a 14th-century monastery and the place where the founder of the Dutch nation lived and was assassinated.

A remnant of the Roman army's presence on the coast of Scotland.

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

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

Atop this former dutch railway office sits an interstellar work of art.

A historic observatory now an astronomy museum beautifully situated at the moat of the Middle Age city centre.

'The Letters of Utrecht' lays out a ribbon of poetry one letter at a time, with no final verse in sight.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

The location of the world's first telescope demonstration.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

A beautiful geyser under environmental threat.

Crypt mausoleum in cathedral's basement contains relics of third century Roman martyr, Saint Vibiana.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Famously misunderstood wonder of the ancient world

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The first declared National Monument in the United States.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

A beautiful Victorian-era cemetery, complete with a miniature village.

Banksy gives themself artistic license with this piece of London street art.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.