What happened to flags on 15 September
2 flags in the atlas carry this date. The sentence under each one is where that is written down, in its own article.
- El Salvador 1912
The flag was hoisted for the first time on 15 September 1912 at the Campo de Marte in San Salvador.
From Flag of El Salvador on Wikipedia, as it read on 2026-08-26
- Republic of the Congo 1959
The new flag was officially adopted on 15 September 1959 and remained unchanged when the French Congo became an independent state less than a year later on 15 August 1960.
From Flag of the Republic of the Congo on Wikipedia, as it read on 2026-08-26
How a day gets onto this site
A flag is here because a sentence in its own English Wikipedia article puts it on this date, and that sentence is printed above. Nothing was worked out from a year, and nothing was written for the occasion. Every sentence names the article it came from and the version of that article it was read in, so you can go and check it.
The calendar is still short rather than full. A third of the year has no page here, because a flag only gets a day when a sentence in its article puts something on one, and plenty of articles never do. Nothing is invented to fill the gap.