Dinosaur bone...
In 1997, John Lambert from Ipswich, U.K. was building a fence in his backyard when he found a large and unusual bone. He thought it could be an important paleontological find but he just put it in his shed where the bone sat for another 16 years. Finally, in 2013, he decided to take it to Ipswich Museum, where experts, astounded, confirmed it to be the bone of a 250-million-year-old pliosaur. But the pliosaur was not native to the English sea, which made the finding even more mysterious.