It was December 1939, Britain had declared war on Germany weeks before, and a baby girl was found abandoned in the doorway of a city centre hotel.
Pat Fitzgerald was three months old when she was found wrapped in blankets on the steps of the Royal Hotel in Cardiff.
Now 71 and a grandmother, she is appealing for help to find the relatives she has never known.
She was adopted by loving parents, but would love to trace her "lost family".
Mrs Fitzgerald, who returned to the spot where she was discovered to make her plea, said: "I've waited years to find out who I am.
"The world has changed a lot - and I hope someone, somewhere now will give me the answer.
"I know it's a long shot after all this time.
"But I have to try to find the answer.
"Someone may have been keeping the secret for all these years, but now is the time to come into the open."
After she was discovered on the hotel steps on 15 December 1939, she spent months in hospital.
She was adopted by steelworker Peter Ross and his wife Edith and spent a happy childhood with them, but she was 27 before she found out about her past.
Mrs Fitzgerald, a retired BT clerk with four children and six grandchildren, said: "I would guess my mother was a young woman whose circumstances must have been absolutely desperate to abandon me in the middle of winter.
"She must have been at the end of her tether.
"But at least she wrapped me up warmly and made sure she left me in a place where I would be found quite quickly."
The Royal Hotel marked the anniversary of the night she was found by giving her VIP treatment.
The manager, Jon Swingler, presented her with an engraved plate reading: "To our Royal lady, given to us on 15 December 1939."
He said: "We would love to help this lovely lady solve the mystery of her life."
Mrs Fitzgerald said: "I have made various appeals over the years including getting the Salvation Army and children's charities involved.
"An anonymous caller claimed she knew a woman who may have been my sister, but it ended up like everything else - a dead end."