An ancient piece of corroded metal is more than it seems: an alien-looking device of intricate dials and cogs; there are over 30 gears inside and some gears have up to 65 teeth on them. Using cutting-edge imaging technology, experts examine what could actually be a 2,000-year-old computer. How can an ancient Roman cup change colour? It's not an optical illusion. It really does change colour from red to green.
How can an ancient Roman cup change colour? It's not an optical illusion. It really does change colour from red to green.