The familiar warning greets visitors at London's train stations and is as famous as Big Ben or the queen. Look at the souvenir stalls and you'll know I'm not lying. There are more "Mind the Gap" T-shirts, coffee mugs, and key chains than those featuring all the royal family put together.
London's transport system, especially the Underground railway with its Tube stations, is one of the quickest ways to travel around the city. If you're a tourist, all you need is a travel card and a Tube map, filled with colorful lines, to get around. It is that simple.
Londoners say that their trains are dirty and overcrowded. They say that at peak hours, it is difficult to get into a car or find a place to sit. On some days, they say, even standing space is at a premium.
As I stood at the platform one day waiting for the Tube to come through the tunnel, I couldn't help laughing at these complaints.
"Londoners are so funny," I thought with a slight grin, hoping no one noticed. "They think that this is crowded! How would they survive back home?"
"Back home" is Mumbai (formerly Bombay), the heart of India. You may have heard stories of the crowds, the noise, and the chaos. But unless you have experienced train travel there, you have not lived life. That's possibly a good thing, because â€“ the joke goes â€“ if you're not an old hand at train travel there, you may not have much of a life left.
It's true that Mumbai has one of the best transport systems in the world. There are trains and buses running late into the night. The trains are (mostly) on time and run like clockwork. More than 3,000 trains each day carry more than a million commuters into and out of the city.
Still, the thought of getting into another train in Mumbai makes me break out in a sweat. I traveled for many years by train, wondering each time if I would reach home alive that evening.
"What an exaggeration!" I hear you say.
Picture this: It is 7:55 a.m. I am waiting for the 8:03 train, which will take me to the other end of the city where I work.
The "ladies" compartment is at the end of the train, next to the driver. I know the train will stop at the end of the platform. But if I want to get on, I have to do what every commuter in Mumbai does â€“ move down to the middle of the platform and jump into the moving train as it slows down on its approach.
I see you recoil in horror. I did, too, at first. Common sense tells us to wait until the train comes to a halt before we board. Experience warns, however, that if you are foolish enough to wait, you will not be able to get in. Forget about finding a seat, you will be fortunate if you can get a toehold in.
It is a hard way to travel. Yet millions do it every day, perfecting the act of soaring into moving compartments into a fine art.
This "sport" isn't just for men â€“ women of all ages jump, too. The fact that they're wearing high heels and saris and carrying shopping bags are but temporary inconveniences to be endured and conquered.
Most will end up standing in a bone-crushing crowd for their entire journey, trying hard not to be pushed out of the train early in the surge of passengers that try to enter and leave at every station. Sardines have a cushy time of it compared to this.
Back in London, as I wait for the Tube to come into the station, I marvel at the order of it all: Passengers wait patiently behind the yellow line. There is no pushing, no shoving. Rarely does anyone wedge in front of you, trying to get in first. And as the train approaches and stops, most people wait for the disembarking passengers to alight before hurrying in.
In Mumbai, if you wait that long, you'll still be on the platform as the train leaves the station.
I don't mind standing during a journey on London's Underground. This level of "crowded" is fine for me. The closest person is still far away, compared to Mumbai.
Watching the eclectic blend of people around me, I cannot help but marvel at this smorgasbord of humanity â€“ every country, language, race, color, and accent is represented here. Well, almost.
On this day, the whole compartment seems to want to get off at my stop. Yet nobody seems to be in a hurry. I still manage to disembark in one piece as the voice says "Mind the gap."
I smile. I am safe. No palpitations today. While Mumbai will always be one of my favorite cities, London, without a doubt, is my train heaven.