“You must understand that an English town is a vast conspiracy to mislead foreigners.” That’s how the writer George Mikes, in his book How to be a Brit, describes the feeling visitors get every time they have to find their way around in England. It’s a feeling most keenly experienced when faced with the enormity of London. What Mike doesn’t explain is that this labyrinth of streets, roads, walks, parks, gardens and views is a challenge for locals too. As if it formed part of the city’s charm, getting lost in London is so inevitable that you end up taking a liking to it. But there is a solution: all you need is The Knowledge.

The Knowledge is the vague name used to describe the exam that aspiring London taxi drivers have to take. That’s right. To drive one of those black cabs you have to sit an exam and it’s not just any old test. It takes candidates an average of three years to pass, if they pass at all.

The “knowledge boys” and increasing number of “knowledge girls,” as The Knowledge students are known, are almost as recognisable as the classic London cabs. They can be seen riding around the city on scooters, an unfolded map in tow, and have something in common with visitors: they’re also trying to find their way. That’s because part of their exam preparation is to travel the 320 routes that appear in a manual known as the Blue Book. That’s just one of the seven different parts that make up the whole exam, however. The most difficult are the oral tests.

The epicentre of The Knowledge, and of London itself since the 19th century, is Charing Cross. This intersection, presided over by an equestrian figure of King Charles I, is the starting point for the tangled mass of 25,000 streets which the would-be cabbies have to learn, although the full content of the exam is a bit wider. Everything within a six-mile radius of this famous crossroads can come up in the exam. Stadiums, emblematic pubs, famous restaurants, monuments, hotels, hospitals, embassies and Nelson’s nose hidden in Admiralty Arch all form part of this exam which, fortunately, isn’t an indispensable requirement to get around London.

In 1884, the first year for which records of this exam exist, more than 1000 candidates applied. Although it might seem like a joke, life hasn’t changed much for cabbies since then: well into the 21st century, London cab drivers are still not allowed to use a GPS. In fact, you don’t need much to get from Covent Garden to Big Ben or from Tate Modern to Buckingham Palace; just a bit of curiosity, a map and a GPS for the most absent-minded. Or ask a cabbie.

If London’s street’s still manage to catch you out, then you can always enjoy the unexpected surprises that the city has to offer. Unique spots that emerge to the bewilderment and surprise of those who believed they were headed in the right direction but have just realised that the destination they were aiming for is at the end of that other street that isn’t called “street” but rather “lane” or perhaps even “terrace.”