Some non-magical people think the oldest pub in London is the White Stag, others say it's the Angel or the Lamb and Flag on Rose Street. All these people who think this are fools and they are all wrong. London's oldest bar, as any wizard will tell you, is the Pierced Cardala.
The popular bar The Pierced Cardala was built by Daisy Doddridge in the early 1500s. The place where the "Pierced Cardala" is located connects the wizarding and non-wizard (Muggle) worlds.
Today, if a Muggle were to walk past the pierced Kardala, instead of a pub, he would see an abandoned and half-destroyed shop. But this was not always the case. Until 1692, Muggles were free to enter the pierced Kardala and no one would turn them back. For them, the Pierced Cardala would have been an ordinary pub, without any magical elements, but in 1692, the International Congress of Magic passed the "International Statute of Wizarding Secrecy" and therefore the pub's keeper had to cover the pub for Muggles. There was some debate that since the Pierced Cardala was located between the Muggle and Wizarding worlds, it should be closed altogether to prevent a stray Muggle from accidentally wandering into the Wizarding World. Despite these risks, the Minister of Magic, Ulik Gemp, made an exception and decreed that the pierced Kardala should continue to exist as a free and peaceful haven for wizards.
Over the centuries, the interior of the "perforated Kardala" changed slightly. It has come to this day as a small, quiet, dark, welcoming pub. It also has some pretty cozy rooms for rent where witches living far from London can spend the night. At one time, Albus Dumbledore, Harry Potter, Hermione Granger and the entire Weasley family remained in the holed Kardala. The bar also has a cellar where the wine cellar is located. The pierced Kardala is an ideal place to learn the gossip of the magical world.
In the eight series of Harry Potter, there are many such episodes that reflect the unusualness of the life of wizards. One such scene is where Harry and Hagrid visit the pierced Kardala. At first, nothing can be seen on the sign of Pierced Kardala, however, as the two magicians approach the bar, a pot painted in black and gold and an inscription that reads "Pierced Kardala" can be seen. Muggles can't see magic, so the sign appeared because wizards approached the bar.
Potterheads, if you're walking down the street and see a blank sign hanging over a store or some other establishment, don't think you're near an abandoned building. You may have reached a place reserved for witches.