http://www.sciencemag.org/news/2018/11/metric-system-overhaul-will-dethrone-one-true-kilogram

The atoms in a sphere of silicon-28 were counted to fix the Avogadro constant and redefine the mole. A copy of Le Grand K, the kilogram standard, can be seen in the sphere's reflection. 

Like an aging monarch, Le Grand K is about to bow to modernity. For 130 years, this gleaming cylinder of platinum-iridium alloy has served as the world’s standard for mass. Kept in a bell jar and locked away at the International Bureau of Weights and Measures (BIPM) in Sèvres, France, the weight has been taken out every 40 years or so to calibrate similar weights around the world. Now, in a revolution far less bloody than the one that cost King Louis XVI his head, it will cede its throne as the one, true kilogram.