A closer look
London black cab drivers must memorize 320 standard routes through 25,000 streets and know the exact location of 20,000 landmarks to pass a brutal test known as The Knowledge, which typically takes three to four years of studying to complete. Neurological studies have shown that successfully completing this grueling mental marathon actually physically alters the driver's brain, significantly enlarging the hippocampus, which is the region responsible for spatial memory. This means that to officially become a cabbie in the British capital, you must literally mutate your own brain anatomy just so you can accurately navigate drunk tourists from a Soho pub to their overpriced hotel without ever having to rely on the perfectly functional GPS app installed on everyone's smartphone
