Not many Americans grow up in a vertical environment. Folks from New York City, I suppose, but that’s about it.

And for those of us from the country or small town or suburbs … our world is a two-dimensional place. Forward and back, left or right.

That is not the case in Hong Kong, however. Which bills itself (among other things) as The Most Vertical City in the World.

That is, to get a sense of what is going on around you … you’ve got to look up. Way up. And recognize that this city is like an iceberg.

Only about 10 percent of it can be seen on the surface.

In Long Beach, in Highland — in Southern California — we live in an environment where any building higher than two stories is a rarity.

We live in our little bungalows, or our two-story apartments or maybe our sprawling suburban tract homes.

Thing is, you can take it all in without craning your neck.

In Hong Kong, to look left-right-forward-back is to miss most of what is going on, at a given moment.

If you are at street level, in a city with hundreds (maybe a thousand) buildings of 30 stories or more … almost all of them devoted to housing after the first few levels … you are looking at only a fraction of the people who share the same longitude and latitude that you do.

The rest are up there.  And it’s not so much that you don’t see them … as it is you don’t even think about them.

This was brought home to me in a modest way the other night.

For the first time, I rode one of the double-decker buses here in town. I was the first person to board the hundred-passenger monster, and I went upstairs and sat in the very front of the bus, looking out the window.

And from there, while traveling some roads I know fairly well — at street level — I realized how much more I could see with just another 15 feet of elevation.

On most of HK’s main roads, the second floor of a building is additional businesses. And now I was looking right at them.

There was a Starbucks here, and I never knew it. A coffee shop there. A sprawling gym. Some sort of factory. A church.

And this was just the second story. What about the third? The fourth? And those hundreds of thousands of lives going on up there on the 20th, 30th, 40th floors?

It’s a little sobering. And the fact that this all takes me back just shows how deeply ingrained my horizontal, SoCal upbringing is.

It may take me years to walk past the 100 feet of frontage of a building and bother to think, “I just passed 500, 1,000 people.”

This is a three-dimensional city. More than any other in the world. And I am one of those least prepared to grasp it. A SoCal guy.