This was one of the first Spidey comics I ever read. I don't think I bought it, but rather it belonged to a cousin who let me read it. I later of course got a copy of my own. In the hundreds of times I've seen this cover, it never occurred to me until just the other day how much the background in this John Romita composition looks like the iconic Time Tunnel from the Irwin Allen TV show.
It makes sense and seems obvious, but I'd just never noticed.