The Sandra Mansi "Champ" photograph, Lake Champlain

Lake Champlain has a monster with a name. Champ. The reports go back to Capt. Crum in 1819 and Sheriff Nathan H. Mooney in 1883. In the summer of 1977, Sandra Mansi of Bristol, Connecticut was on a family trip along the Vermont shore, north of St. Albans, close to Missisquoi Bay. With her were Anthony Mansi and her two children, Heidi and Larry, aged 11 and 12.

July 5, 1977. Around noon. The family had stopped near a small bluff, and the children were in the water. "I could see a turbulence, like how a school of fish look." Her first thought was that it was a sturgeon.

"Then the head came up, and then the neck came up, and then I could see the back." About 150 feet from shore, a dark, leathery-looking animal had risen from the lake. It had a small head, a long neck held some six feet above the surface, and a rounded back. She watched it turn its head and neck and look around. "You could see the water coming off it."

Anthony went back to the car for the camera. He came to the top of the embankment and saw it. He was screaming for the kids to get out of the water. "It never gave any indication it knew we were there."

Then it looked over its back. Sandra took the picture with her Kodak Instamatic. One exposure. After maybe five minutes, the back went down. Then the neck. Then the head.

The family kept the print private. By Sandra's account, the negative was thrown away. "I've never kept negatives. What good are negatives?" On June 30, 1981, the photograph ran in The New York Times and was reprinted widely. "No fish can hold itself up six or eight feet out of the water," she later said.

In 1981, B. Roy Frieden of the University of Arizona's Optical Sciences Center found no montage and no sign of tampering. He saw a separate set of surface waves coming from the object. It was real, and it was in the water. What it was, he could not say. In 1982 Paul H. LeBlond used the length of the wind waves to estimate its size at 4.8 to 17.2 metres.

In 2003 Benjamin Radford recreated the scene for the Skeptical Inquirer, using an Instamatic 110 and a marker at 150 feet. The reconstruction placed the visible form about 3 feet above the water and about 7 feet long, leading Radford and Joe Nickell to favor a floating log or tree stump. Nickell doubted that a giant creature could hide in a bay no deeper than 14 feet. Darren Naish suggested a large mass of wood with a neck-shaped branch. Even so, Radford and Nickell called it "the most credible and important photographic evidence of the existence of lake monsters."

In 2013 Robert E. Bartholomew added a new layer. He published a 1980 letter from Vermont state naturalist Charles Johnson. It recorded that the Mansis had told him they "buried it (or burned it…)". In a 2002 interview, Sandra seemed to say she knew the spot but would not reveal it, "because of the idiots." No one has shown the photograph was faked.

Sandra told her story on Unsolved Mysteries in 1992. "I'm telling you, in that lake, there is something extraordinary." In 2012 the family gave the original print to ECHO, Leahy Center for Lake Champlain. It is shown in person there once a year, on Champ's birthday. Sandra Mansi died on March 31, 2018. She was 74.