There’s a highway that formed a loop around the city where I grew up and we used it pretty regularly, but mostly only the western half (since we lived on the west side of town). My parents explained the concept to me that it had “belt” in its name because it circled around the city like a belt goes around a person. This idea intrigued me and I eventually asked my parents if someday we could drive all the way around it. My dad seemed kind of surprised but said we could sometime. I got excited and started planning for things we would need, like a tent and food, since it would obviously take a long time.
The highway’s only about 25 miles/40 kilometers long.
I remember my Dad teaching me about highway numbers back when I was a kid, so I know that the 4 means it's part of a loop, being odd means it runs mostly N/S, and being a low number means it's on the west side of the US.
The Dewey Decimal System is still a mystery to me, though...
I believe if the first digit is even in the 3 digit highway number, it connects, if it's odd then it doesn't. There's a cool video about it by cgp grey and a whole Wikipedia on it