Lourdes in the South of France is the place where Mary, Mother of Jesus, appeared on a number of occasions (called apparitions) to a girl by name of Bernadette Soubirous. Bernadette was a 14-year-old miller's daughter.
She reported 18 apparitions of A Lady. Despite initial skepticisim from the Catholic Church, these claims were investigated and later found to be worthy of belief. The apparition seen by Bernadette is now known as Our Lady of Lourdes.
Bernadette became a nun at the age of 22, joining the convent of the Sisters of Charity. The pope made her a Saint in 1933.
You can read more about Our Lady of Lourdes on the wikipedia: wikipedia:Our_Lady_of_Lourdes