A Colorado grandfather finally completed the world’s largest jigsaw puzzle four years after starting the project when the brain teaser’s maker sent him the 60,000th piece he was missing.

Lou Salas is a certified puzzle fanatic who estimated he spent anywhere from 800 to 1,000 hours carefully constructing “The World’s Largest Jigsaw Puzzle by Dowdle,” KRDO reported.

The puzzle, a 60,000-piece world map, took up his entire puzzle room. He spent a painstaking four years carefully constructing each of the puzzle’s 60 quadrants with help from his now 8-year-old granddaughter.

When he was working on the puzzle’s 17th section, he realized he was missing one piece.

“I didn’t sleep that night. One piece ruins the whole thing,” Salas told the outlet.

Salas refused to let so many months of work — and the $600 he spent on the puzzle — go down the drain.

Dowdle, the company behind the puzzle, eventually shipped him the final missing piece he needed, bringing the years-long project to a close last weekend.

Salas said finding a way to put all 60 sections together “was the biggest puzzle within the puzzle.”

His friends set up an 8-foot by 29.5-foot styrofoam table in his garage and suspended him from the ceiling so he could carefully lay down each quadrant — not dissimilar to how cranes lift and move materials on construction sites.

As the puzzle master reflected on his accomplishment, he decided to deconstruct the completed puzzle and donate it to one lucky fanatic or organization free of charge — on the sole condition that they too “pay it forward” when they’re done.

“You can’t put it into words or a price on it or anything. If someone can do it, that’s good enough for me,” he said.

“I’m gonna miss it. It became part of me for this little segment of my life,” Salas said.