Waterstones Piccadilly is London's largest bookshop, and claims to be the biggest bookstore in Europe.
The shop is spread over six huge floors of books with more than eight miles of shelves, containing more than 200,000 titles.
Simpsons of Piccadilly building
The Waterstones at 203/206 Piccadilly is the company's flagship store. It's housed in a Grade I Listed 1930s art deco building that used to be a department store called Simpsons of Piccadilly.
Opened in 1936, the new Simpsons building was designed to showcase the whole range of clothing offered by Simpsons and Daks (the latter is a portmanteau of 'dad' and 'slacks'). The architects and designers were influenced by the Bauhaus, modernism, futurism and cubism.
The building was the first in Britain to feature uninterrupted curved glass windows at the front.
You can still see some of the original fixtures inside the shop, including the 90-foot chromium light fitting suspended from the ceiling, illuminating the stairwell, and the steel and glass handrails.
Waterstones Piccadilly Sections
As well as the usual best sellers and new releases, Waterstones Piccadilly has sections on Travel (lower ground floor); First Editions (on the first floor); Biography, Humour, Film & TV, and Transport (third floor); and History, Politics, Languages, Religion and Business (fourth floor).
In 2015, Waterstones Piccadilly expanded their Children's Section on the second floor.
The (Piccadilly) Circus-themed area now takes up two-thirds of the building's second floor.
The Russian Bookshop
There's even a bookshop within the main bookshop. The Russian Bookshop opened on the fourth floor in March 2012, and stocks around 5,000 titles. It's staffed by Russian-speaking booksellers.
5th View Bar
On the top floor of Waterstones Piccadilly is a bar, 5th View Bar & Food, with a view over the rooftops towards the Houses of Parliament, Westminster Abbey and the London Eye.
There are two Cafe Ws inside.
The one on the ground floor is useful for takeaways in this busy corner of London; the second, on the Mezzanine among the plentiful stationery and gifts on offer, is a good place to settle if you're looking for a bit of peace and quiet.
Waterstones' lock-ins and sleepovers
In 2014, Waterstones Piccadilly hosted a sleepover for 10 lucky prize-winners.
The event was organised after a Texan tourist, David Willis, got locked in the Trafalgar Square Waterstones when it had closed for the night. Willis tweeted for help and attracted 12,000 retweets, as well as lots of media coverage and discussion on social media.
The bookshop also hosts a variety of special events, including author events and writing classes.
The London Sci Fi and Fantasy Book Club meets at Waterstones Piccadilly once a month, and the store itself has its own book club.
Love bookshops? So do we. Read more:
Mapped: London's Independent Bookshops