Once housed in the towers of this Gothic church, this 17th century clock still ticks today.

One of the Leiden's oldest pubs is also the birthplace of the Heineken star.

The 20-mile causeway that separates the Netherlands from the sea.

Science meets wall art to highlight the beauty of famous mathematical equations.

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

Peek through a transparent pyramid and drink in the mountain made of books.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

A strangely curved lamppost stands tall over this avenue in Rotterdam.

A five-story homage to tea times past.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

An architectural oddity hides in plain sight on this iconic London bridge.

Where condemned pirates met their grisly end at the gallows on the River Thames.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

Sculptor Antony Gormley used chaos theory and fractal growth to design his tallest creation.

Putting the "mod" in "modular" since 2000.

A sculpture of a famous ape who was once a beloved household name in London.

Taxidermied animals galore, by appointment only.

This striking statue brings a scene from the African savannah into central London.

A clock designed to run with perfect accuracy for 10,000 years.

Hidden in the courtyard of the Victoria and Albert Museum is a little-known tribute to two celebrity pooches.

The bones of two medieval royal lions were discovered at the historic fortress.

The plunge pool is a surviving relic of a rowdy royal residence.

A giant scrawl on the skyline of south London.

A relic of Victorian grandeur hides beneath a busy South London road.