The Sky Disc was discovered in Germany in 1999. Experts believe the Nebra Sky Disc was a calculator to help Bronze Age people predict the best times for sowing and harvesting in spring and autumn from the Middle Bronze Age/1600 BC
So you know your chronological age, but what's your age on the inside? Professor Ulrik Wisloff director of the KG Jebsen Centre for Exercise in Medicine at Norwegian University of Science and Technology, and his team have developed an online calculator to help you figure out your personal fitness age. Try it here.