Precision: The Measure of All Things Mass and Moles (2013– ) watch online HD

Deep underground in a vault beneath Paris lives the most important lump of metal in the world - Le Grand K. Created in the 19th century, it's the world's master kilogram me, the weight on which every other weight is based. But there is a problem with Le Grand K - it is losing weight. Marcus explores the history of this strange object and the astonishing modern day race to replace it.