Hidden beneath the streets of London is a secret subway that only carried mail.

England's most famous front door has an accidental doppelganger.

The birthplace of the ferocious William the Conqueror, this castle is awash in medieval history.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

On the walking path from Monterosso to Vernazza, a small shrine dedicated to feline friends.

Inscribed on the gate are the names of 29 figures from the University's first five centuries.

Order cookies baked by cloistered nuns in a 400-year-old monastery.

The location where the American Revolution ended.

A bronze kitty adorns the grave of the polar explorer who brought the original feline to the Antarctic.

Science fiction's grandfather has a fittingly marvelous tomb.

The artist and his brother are buried in a landscape straight out of a van Gogh painting.

This replica of the Greek structure is in the heart of Nashville.

This clifftop arch is a natural stunner.

The first hand-illuminated, hand-written bible since the invention of the printing press.

This lone survivor of a regional franchise still slings delicious burgers and colossal servings of fries.

This stained glass window designed by Tiffany Studios is hidden behind the circulation desk of a public library.

Located on the banks of the St. Lawrence River, this mansion is home to a massive art collection.

Da Vinci's equestrian statue, 500 years in the making.

A devilishly named gorge that was a sign of salvation for many pioneers.

The entire length of the border is marked by a 20-foot-wide slash through the trees.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

An isolated village literally built into the crevices and rock formations of a mountain.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.