This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

This residence straddles a border between Belgium and the Netherlands.

Not many houses move across borders, this one did it twice.

This building once stood at the center of a butter war.

A tribute to smugglers and the Butter Wars.

A maze of crosses marks the jumbled divide between the Netherlands and Belgium.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

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

A floating cat sanctuary on an Amsterdam canal.

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

This natural hill rose another 130 feet from the debris and rubble added after World War II.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

This 600-year-old home seems to defy physics.

The last bastion of Roman presence north of the Alps looms over a German town.

An intriguing three-sided folly is a testament to one man's devotion to Catholicism and the number three.

The longest and tallest aqueduct in Britain can actually be sailed across.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

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

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.