Researchers have discovered that the colour change of the glass chalice, known as the Lycurgus Cup, is a result of the Romans' pioneering nanotechnology work. They'd loaded the glass with tiny ground particles of silver and gold, as small as 50 nanometres in diameter. The exact mixture of the precious metals suggests they knew what they were doing.

Read more: http://bit.ly/1dacjSv via the Smithsonian Magazine. Image: The Trustees of the British Museum / Art Resource, NY)