— -- A family beach outing turned terrifying last week when what was thought to be a washed-up buoy turned out to be an active bomb.
"My children took their boogie boards down and we were going out to the sea," Kelly Gravell of Burry Port, Wales, said. "We saw a large object on the beach, so we thought we’d have a little look.
"We get things washed up all the time, so we thought it was a buoy. We never thought for one second it was a bomb."
Gravell told ABC News she, her husband, and two young children went to their local beach for a picnic on Aug. 12, when the kids noticed something wash onto the sand.
That's when, she said, Erin, 6, and Ellis, 4, began posing for photos with the huge metal ball.
"We were more fascinated by the barnacles on it," Gravell added. "My son was touching it and was knocking on it a little bit, and that was it really."
Five days later, Pembrey Country Park officials announced on their Facebook page that the “buoy” discovered on the seashore was a United States military mine bomb.
Gravell said she and her husband, Gareth, were notified of the news by a friend who saw photos of their children with the bomb on Facebook.
"The realization that it was a bomb -- it was completely shocking for us," she said. "We realize now just how lucky we were."
Allison Thomas-David, press and communications officer for Carmarthenshire County Council, said it's common for objects to wash ashore in the area where the mine was found.
"It very much looks like a buoy, which we get on the regular, but around it was gooseneck barnacles," she said. "Of course as the barnacles started dropping off, that’s when we could see writings exposed."
The object reportedly dates back to World War II, which ABC News has been unable to confirm.
While she could not verify what was printed on the bomb, or what kind of bomb it was, Thomas-David said it still remained clear that the object was indeed an explosive.
"This was picked up by the coastguard who then notified the bomb squad," she added. "Obviously we evacuated the beach straightaway. It detonated in a controlled explosion 6 p.m. Monday evening."
Gravell said she and her family went down to watch the detonation together.
She added that in light of their experience, they will be more mindful of foreign items that wash up onto the beach.