13 May–13 October 1917; principal public solar event 13 October / T022
Fátima and the 'Miracle of the Sun'
Cova da Iria, Fátima

Witness account
Three shepherd children reported a series of Marian apparitions beginning in May 1917. A large crowd assembled on 13 October, and accounts described unusual apparent movement and changing appearance of the Sun. Later writers incorporated these descriptions into UFO arguments. The children's religious claims and the crowd's reported solar experiences are related historically but are not interchangeable observations.
Public record
The shrine's documentary chronology identifies the first priestly interview on 27 May and cites preserved questioning records. It also identifies contemporary newspaper coverage of the October event. Its chronology distinguishes these records from Lúcia's much later memoirs about earlier experiences. Crowd estimates vary, and a crowd's presence does not establish that all present described precisely the same thing.