The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
RATP's[3] own history page and EarthSky's[2] science-history article both give 19 July 1900 as the inauguration date of the first métro line.
Independent science-history article corroborating the 19 July 1900 opening.[1]
RATP's own history page for line 1 gives the 19 July 1900 inauguration date.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.
