A bit of history: the metric system which is now the universal standard for measurements was created over 200 years ago. World Metrology Day commemorates the signing, on 20 May 1875, of the Metre Convention, an international treaty designed to ensure that everyone around the world used the same metric system to measure weight and length, in order to ensure fair trade. The Metre Convention has since been ratified by over 100 countries and economies. 

Celebrated on 20 May each year, World Metrology Day helps the public to understand what is meant by the science of measurement and why we are so dependent upon it. This little-known science underpins countless aspects of our daily lives. Every time we buy a kilogram of oranges, use the GPS in our car to navigate, swallow a pill, cross a bridge or enter a building, we should spare a thought for the metrologists who made this possible. Thanks to the metric system, an architect trained in Sudan will be able to design an office building in Mexico, as the standard measurements will be the same in both countries.

Source: Text & Image: https://www.unesco.org/en/days/metrology