Fredrik Palmqvist, chairman of the Turbine cultural association in Kalmar, said he and other group members were doing some cleaning Monday in the cellar of the city wall, which the group often uses for meetings, when he made the discovery, The Local.se reported Tuesday.
"I put a small shovel into a pile of dirt and heard a distinct 'clang,'" Palmqvist said. "I got down on my hands and knees and began scooping away the dirt. At first I thought it was a food canister from the military."
However, he soon cleared off the item and saw what appeared to be a rusty bombshell.
"It came as quite a shock. I picked it up in my hands and ran out of the room," he said.
Palmqvist said he sent the rest of the group home and called police.
"The experts in the bomb squad were 100 percent certain it was some sort of military ordinance. But because it was so rusty, they weren't sure how old it was," Palmqvist said. "But one said it might be from the 1800s."
"They don't know if it was live, but that older ordinance is especially dangerous because it is so unpredictable," Palmqvist said. "It's frightening to think what could have happened. Nevertheless, it's an amazing historical find and our group very much hopes to get the shell back."