Thé golden standard is the meter...
It is derived from the circumvence of the earth at Paris:
The meter was designed to 1/10.000 of the distance from the north-pole to the equator, they went to great lenghts to measure the exact length of this small factor.
The idea is that the earth belongs to us all, and by deriving the meter from the earth it cannot be claimed by a country, political party or religion (in the spirit of the french revolution at that time).
Sometime we gave up on this idea because the circumvence of the earth changes, and measuring it is quite an exercise.
Ton