More than a million titles fill the labyrinthine shelves of this prestigious private library.

A Roman spa buried deep beneath the City of London.

This secluded walkway overlooks a magnificently wild London green space.

A historic arboretum and non-conformist, non-denominational park cemetery.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

This network of narrow, medieval passages has the most delightful name.

Keep a lookout for replicas of this wooden soldier hiding in plain sight all around town.

A chaotic collection of coin-operated slot machines designed to delight and disturb in equal measure.

This 1920s Dutch barge is now a floating bookstore.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

Following the trail of an old metro line, this scenic path is haunted by a creepy spriggan statue.

Children's hospital in London that operates on royalties received from Peter Pan, which J.M. Barrie signed over in 1929.

A building that survived WWII, possibly on the virtue of its name alone.

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

A network of concealed passageways lies within a busy London Underground station.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

Artists and musicians now rule over this former rail station.

The collection contains over 25,000 items and details the painful dental practices of the past.

Black cat statues guard this temple-like Egyptian revival factory.

An abandoned tank sits in an empty London lot as a symbolic middle finger to local city planners.