Which city requires aspiring taxicab drivers to undergo years of training?

There's a reason London's black taxi cabs are so prestigious. The requirements for driving them are among the strictest in the world.

Anyone hoping to do so must pass "The Knowledge," a notoriously difficult series of tests on more than 320 routes, 25,000 streets, and some 20,000 landmarks and places of public interest, from tourist destinations to museums, parks, churches, theatres and schools. All must be memorized. The process typically takes from two to four years to complete and involves a number of oral exams. The end result has been described as comparable to having an atlas of London implanted into your brain.

Once licensed, the cabbies are forbidden from using GPS devices to navigate England's capital; the metropolis' intimidating traffic must be braved by memory alone.

As you can imagine, the time and dedication needed to achieve this standard has made many black taxi drivers angry with what they see as a lack of regulation for their competitors.

Drivers are none too pleased with the rise of Uber and other ride-share services, whose standards are, shall we say, a little laxer.