As Kate Crowley walked the last mile of the 1,550 she tramped around Lake Superior, joined by cheerful supporters along Duluth's Lakewalk, she realized an accomplishment that she and husband Mike Link had never anticipated when they set out 145 days earlier: They'd made people happy.

"Not just those who met us and walked in with us, but all the people who followed us on Facebook and made comments throughout our journey," she said. "What could be better than making people happy?"

Last Saturday, Crowley and Link completed the audacious goal of walking the shoreline of the world's broadest expanse of freshwater. They sought to document Lake Superior's condition as of 2010 to aid future environmental discussions. But the idea that they were two grandparents in their 60s also was meant to inspire others to dream big.

That said, Link's knees just about did him in.

"I am feeling better now after two days off the trail," he said this week, "but at the end, they were making sleep almost impossible." Yet when Duluth finally came into view, "I was not really ready to quit. This day-by-day traveling and exploring is addictive."

Those who want to follow their journey still may do so through their website (www.fullcirclesuperior.org), which includes video of the shoreline and of the people they met in Wisconsin, Michigan, Canada and Minnesota.

The couple, longtime naturalists from Willow River, Minn., found that residents love their stretch of shoreline, but don't often consider the larger lake. "They do not know what is happening on the other side of the pond," Link said. "I tried to make the point that if we were all eating our cereal out of the same bowl, we would want to know when someone spit in the bowl. We need a lake perimeter discussion that never ends."

Overall, they're optimistic about the lake. Yet they were sobered in late July when a pipeline leak in Michigan spilled more than 800,000 gallons of oil into the Kalamazoo River, which flows into Lake Michigan. "The oil spill demonstrated that big problems are still possible," Link said. "We need to begin to value clean air and clean water above profits. Jobs can be had by making good decisions as well as bad."

Each noted the 10 days spent canoeing along the northeast corner of the lake, where the Canadian shoreline was impossible to walk, and dipping their cups in the lake. "To just drink the water straight up -- no filter, no purifier -- still blows me away," Crowley said.

Over the coming months, they'll share their data with various groups, such as the Natural Resources Research Institute in Duluth and the SEEK program, which administers the Minnesota Report Card on Environmental Literacy. Tony Murphy, an associate dean at St. Catherine University who pioneered the report card idea, said he's especially interested in people's attitudes toward Superior and water issues in general.

While physically in great condition after averaging 10 miles a day for almost five months, Crowley said that emotionally she's feeling "a bit lost" at the moment, "probably because we are still coming down from the major high of our return."

And while their walk was memorable, "we will not do it again," Link said. "But that is not because we did not enjoy it. I know that it was doing it in tandem with Kate that made all the difference. My bad back and knees argued against continuing many days, but Kate's determination and the promise of new discoveries every day made quitting impossible."

Kim Ode • 612-673-7185