Opening of the Paris Métro Line 1

The Paris Métro's Line 1 opened on July 17, 1900, just in time for the Exposition Universelle. Engineer Fulgence Bienvenüe oversaw construction of the 8.5-mile underground route using cut-and-cover methods through dense city streets. Electric traction replaced steam, with wooden-bodied cars operating on 750 V DC third rail. The line alleviated severe traffic congestion and set standards for rapid transit worldwide, including deep-level stations and Art Nouveau entrances by Hector Guimard. Its immediate popularity carried millions of passengers, spurring further expansion and influencing subway designs in London, New York, and beyond. Today Line 1 remains the busiest on the network after automation upgrades.