Signing of the Metre Convention by 17 nations leading to the establishment of the International System of Units.

The Metre Convention, signed on May 20, 1875, is an international treaty that established a worldwide framework for uniform measurement standards. Initially agreed upon by 17 nations in Paris, the Convention led to the creation of three pivotal institutions: the International Bureau of Weights and Measures (BIPM), the International Committee for Weights and Measures (CIPM), and the General Conference on Weights and Measures (CGPM). Its primary goal was to standardize the metric system—particularly the metre and the kilogram—ensuring consistency in scientific, industrial, and commercial measurements. Over time, it evolved to support the International System of Units (SI), facilitating the adoption of advanced definitions based on fundamental constants of nature. The treaty remains crucial today, with more than 60 member states, underpinning global efforts to maintain and refine the precision of measurements across disciplines.