Dense multistory parking underground.

In South Korea, you usually don't see parking lots the size of several football fields like in the U.S., even around venues that generally attract a lot of cars, even in suburban areas. Instead, there are several stories of parking lots under every large building. Above-ground space is simply too valuable to waste on parking.

Unfortunately, you can't install solar panels underground.

> Dense multistory parking underground.

I sometimes forget there are parts of the world where you can go more than about a metre down without breaking out the Kango hammer.