I'm a Londoner who always rides the Tube. Here are 10 features of the Underground that would surprise most Americans.

While it’s ridiculously busy at rush hour and way too hot in the summer, the Tube is an essential part of life in London.

As a local, I sometimes use the public transit system — formally called the London Underground —more than four or five times on some days, as it’s often the quickest way to get around the city.

I can thank the London Tube for saving me from missed flights or arriving late for an interview.

Nonetheless, I can’t count how many times I’ve seen tourists staring at a Tube map, trying to make sense of its seemingly endless tangle of colored lines.

Even as someone who uses the Tube all the time, I have the Citymapper app at the ready when taking an unfamiliar route.

The Tube also has some rules — both official and unwritten — that I would consider necessary for any tourist coming to London.

If you have seen what happens when someone stands on the left-hand side of the escalator, you will know what I mean.

Here are 10 surprising things you probably don’t know about the Tube, including some that might be useful to know as a tourist.