UNIQUE AND PRICELESS
The Kilogram is the only base unit
that still relies on an artifact.
The International Prototype ‘K’ is
kept hidden inside a vault in the
basement of the Bureau Internatio-
nal des Poids et Mesures BIPM in
Sèvres near Paris, France.
Only once every year, the safe is
opened for eyeball inspection of ‘K’
during a little ceremony.