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.
Happened as dated, per the source: "opened to the public in Washington, D.C., on this day in history, Oct. 9, 1888".
Britannica's own entry on the Washington Monument is a respected general reference, though the page itself could not be fetched to quote directly.
Fox News states the monument "opened to the public in Washington, D.C., on this day in history, Oct. 9, 1888," matching the pin's stored date exactly.
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.
