A dedicated grandfather from Colorado has triumphantly completed the world’s largest jigsaw puzzle, an endeavor that spanned four years, after the manufacturer sent him the elusive 60,000th piece that was missing from his set.

Lou Salas, an avid puzzle enthusiast, estimates that he devoted between 800 to 1,000 hours to meticulously assembling “The World’s Largest Jigsaw Puzzle by Dowdle,” as reported by KRDO.

The puzzle, which features a 60,000-piece depiction of a world map, occupied his entire puzzle room. Over four years, Salas systematically pieced together each of the puzzle’s 60 sections, often with the assistance of his granddaughter, who is now 8 years old.

However, while working on the 17th section, Salas discovered he was missing a crucial piece.

“I couldn’t sleep that night. One missing piece can spoil the entire puzzle,” Salas shared with the outlet.

Determined not to let his significant investment of time and the $600 spent on the puzzle go to waste, Salas persevered in completing the colossal challenge.

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.