A man found a stegosaurus skeleton during a stroll on his Colorado property. He could make $6 million from it.

• Jason Cooper discovered a stegosaurus fossil on his Colorado property in May 2022.
• The fossil, named Apex, is about 70% complete and could fetch up to $6 million at auction.
• Apex will be sold by Sotheby's in July, with some paleontologists arguing it belongs in a museum.

On his 45th birthday in May 2022, Jason Cooper was strolling through his Colorado property when he came across part of a stegosaurus bone sticking out of a rock wall.

He began excavating it, cleaning and assembling the skeleton, and named it Apex.