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: "Tokyo Skytree was completed on Leap Day, 29 February 2012, with the tower opening to the public on 22 May 2012".
Comparison episode covering Tokyo Skytree alongside the Eiffel Tower.[1]
Wikipedia confirms Tokyo Skytree's "opening to the public on 22 May 2012," an exact match to the pin's stored date.
The Embassy of Japan in the UK's own webmagazine piece, "Tokyo Skytree Opens," published May 2012, supports the pin's claim, though the page returned a 403 error and could not be retrieved to confirm the exact date wording.[1]
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.