A man who was taking a stroll in Chicago on Friday morning ended up walking onto a frozen Lake Michigan.

Fox 32 reports that first responders rescued the man, a 24-year-old international college student at around 7 a.m. in the Hyde Park neighborhood. He had been seen on the lake at about 1,000 feet from the shore, near the Lake Shore Drive expressway. It was about 12 degrees outside.

“I was strolling on ice because I found it was solid, and I found it relaxing,” the student told the news outlet. “I heard police sirens, so I came back.”

But the Chicago Fire Department’s Jason Lach said the man didn’t know he was on water until he couldn’t make his way back to shore. That’s when someone in a high-rise building spotted the student and reported the incident.

“He was out just for a walk back home … he had no idea he was on the ice at first,” Lach said. “He was more than 1,000 feet offshore on broken ice.”

Fire and police officials rescued the man, who was transported back to land on an inflatable canoe just after 8 a.m. “Our lake front spans 25 miles,” Lach told WGN 9. “[The ice is] not always inches thick.”

In fact, at one point, a first responder fell through the ice and the rescue crew came upon spots with open water. The rescued man had been on the lake for about 40 minutes. He was later issued an Administrative Notice of Violation for Disorderly Conduct.