He definitely didn’t expect to find this in his backyard!

Sometimes, when people buy a house, they find some hidden, forgotten treasure stashed away somewhere. That also happened to the American John Sims from Tuscon, Arizona. When he studied the blueprints of the house he’d just bought in 2015, he made a special discovery. The blueprints showed an ‘extra room’ in the backyard. What he found is definitely extraordinary!