Four thousand separate panels, decades of work, and one deck of cards dictating everything.

But for all the effort those literary types put into their fictional maps, there’s probably never been anyone quite like Jerry Gretzinger.

As explored in a recent video from the YouTube channel People Make Games, Gretzinger—a genial octogenarian from Michigan—has been working on the same fictional map since the 1960s.

Today, the map comprises something like 4000 panels, and the channel’s video captures Gretzinger’s first attempt to assemble it in its entirety for over a decade.