Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Hear the quietest sound from across the dome.

Catacombs turned marketplace.

Rebuilt remains of a temple to Roman god Mithras.

The curios of pharmacist and collector Henry Wellcome.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Eighty million natural history specimens call this gargantuan museum home.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

One part local history, 99 parts gruesome haunted house.

A student driver's nightmare.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

The last remaining colonial-era Italian church in Old Goa.