U.S. Bank Stadium cost more than $1 billion, took nearly 3½ million labor hours to build and is clad with thousands of zinc metal panels.

A model of the arena made by a Minneapolis man cost about $50 in materials, required about 400 hours to build and is covered with thousands of toothpicks.

Greg Kelly, a 66-year-old retired hobby shop owner, recently completed a seven-month project to build a 4-foot-long model of U.S. Bank Stadium out of balsa wood, bamboo skewers, strips of wood from a corn crate and about 6,400 toothpicks.

“Once you get into something, you have to keep it up,” he said. “I have to always be building something.”

The stadium isn’t the only replica Kelly has made, although it’s arguably his finest. The California native has decades of experience in building models.

He was a young man who had never heard of balsa wood when he started a hobby shop in Orange County. Over the next 43 years, he taught himself how to build model planes, boats and rockets while running his store.

A few years ago, he retired and he and his wife moved to back to Minnesota, where she’s from. They came for the weather. Palm Springs, where other relatives lived, was too hot for them.

But while he was done with work, Kelly wasn’t done with model making.

He’s kept himself busy in Minnesota by making scratch-built models of local landmarks such as the Swede Hollow Café in St. Paul or the Cup and Cone ice cream shop in White Bear Lake.

Kelly’s work on his toothpick stadium began after he made a couple of trips to the real arena this year to take photos and make sketches of the unusual angles of the building’s roofline.

Next he built a rough, palm-sized model of the model before constructing a detailed venue suitable for HO-scale football players and termites.

He was inspired to make the model because he likes the building’s dramatic shape, and because it will be in the national spotlight soon when it hosts Super Bowl LII. It’s also been part of his way to celebrate becoming a Minnesotan.

‘An extreme challenge’

The project turned out to be his biggest little building, and required trimming the pointy tips off thousands of toothpicks. It took three 8-ounce bottles of wood glue to put it all together.

“This one presented an extreme challenge,” Kelly said.

Toothpicks aren’t heavy, but he said it was still backbreaking work until he figured out he could sit on a bar stool to reduce the amount of time he spent bending over, tediously gluing tiny pieces of wood together.

He kept building even when he learned over the summer that the prostate cancer that he thought he’d beaten with chemotherapy was back again.

Working on the stadium helped him forget about his troubles.

“You’re tuning out all the pain and suffering you may have,” he said.

He finished last month just before a bout of salmonella poisoning landed him in the hospital for five days.

“I felt really relieved,” he said of completing the model. “It was a real ordeal to get through it.”

His model reproduces the U.S. Bank Stadium’s five distinctive, giant exterior doors, but the interior is unfinished. That’s partly because Kelly has never been inside the real stadium to see a game.

He wanted to go to the U2 concert at the stadium in September, but his health kept him from going.

He said he’d eventually like to donate his model to a school, museum or library if it could be put on display somewhere.

“In my medical condition, I was so happy to finish it up,” he said. “I just wanted to put my spirit into that work.”

But he’s already working on his next project: a model of his sister’s hair salon building.