A line of people stretched down the sidewalk outside Pie & Mighty, a south Minneapolis pie shop, on Saturday, its opening day. It happened to be Pi Day, the annual celebration of the mathematical constant, pi (whose first three digits, 3, 1 and 4, form the date March 14), which many people observe by eating the titular baked dessert.

The timing of the opening was sheer coincidence, said co-owner Rachel Swan. The shop's license to operate had just been issued the day before.

"It's perfect timing," Swan said.

Well, kind of — if you don't count the state of emergency Gov. Tim Walz declared Friday in response to COVID-19. In an effort to slow the virus' spread, officials advised canceling any gathering of 250 or more people. Museums, theaters, courtrooms, sporting events and other organizations around the metro area closed. Some large churches told parishioners to stay home on Sunday and watch services via livestream.

But as Pie & Mighty demonstrated, not every public space had become a ghost town. Neon "OPEN" signs glowed through windows of restaurants, bars, laundromats, cigar stores, bike shops, coffee shops and liquor stores. Some grocery stores may have run out of toilet paper or hand sanitizer, but otherwise it was business as usual.

The Three Rivers Park District announced it would cancel some events but keep open its regional parks, park reserves and trails around the metro area. The parks' 27,000 acres allow plenty of fresh air and space for people to practice the social distancing that health experts recommend.

"Getting out to take a walk, ride your bike or breathe some fresh air can be very helpful during stressful and uncertain times like these," said Superintendent Boe Carlson on the Three Rivers website.

The Minnesota Department of Natural Resources' 75 state parks were open. So were at least some ski areas, community centers and movie theaters. The Walker Art Center was closed, but the adjoining Minneapolis Sculpture Garden was open as of Saturday. St. Paul's St. Patrick's Day parade was canceled Saturday, but Irish bars and other organizations were already festively observing Tuesday's holiday.

Back at Pie & Mighty, customers jammed the front of the tiny shop, while staff and volunteers ran back and forth from the kitchen slicing and handing out pieces of cherry crumble, Key lime, maple pecan and Hoosier mama sweet cream.

Swan and her business partner and spouse, Karen "Ratchet" Mattison, stood outside and greeted people in line, many of whom had become fans over the three previous years, when Swan and Mattison sold pie from a church basement and developed an e-mail list of 4,000.

Most of those waiting in line appeared nonchalant about the virus' threat — or at least weren't letting it keep them from pursuing pie.

"I just don't care today," said Margaret McInerny, 70, of Minneapolis. "Pie's exciting. Pie knows no boundaries."

Swan definitely was not practicing social distancing as she visited with customers in the line. She chatted, laughed, even hugged.

By about noon the shop had sold out of pies — 120 in two hours. But even latecomers who were turned away cheerfully promised to come back. Swan, having started baking pies in 2016 as a way to manage depression, believes in the power of pies to make people happy, even in worrisome times.

"You never see anybody eating pie and crying at the same time," she said.

Katy Read • 612-673-4583