It's hard to know who was more taken by surprise.
America's famous aviatrix Amelia Earhart had not intended to land in a field near Londonderry.
Nor, on 21 May 1932 - 90 years ago today - could Robert Gallagher, the field-owning farmer, have been expecting an uninvited transatlantic traveller.
Now a series of events is taking place in Derry to commemorate the 90th anniversary of the historic landing.
Earhart's unexpected landing broke three records.
She was the first woman to fly across the Atlantic solo, she also held the fastest flight time over the ocean, and was the only person to have twice flown the Atlantic.
The Amelia Earhart STEM (science, technology, engineering and maths) Challenge is the brainchild of Clare Doherty, the great-granddaughter of Robert Gallagher.
A teacher, who heads up the Technology Department at St Mary's College in Derry, she is also the Royal Academy of Engineering's Connecting STEM Coordinator.
The Ballyarnett landing
- Amelia Earhart had taken off from Harbour Grace, Newfoundland in Canada, in a bid to become the first woman to fly solo across the Atlantic.
- Hoping to land in Paris, bad weather and technical problems altered her course.
- On 21 May 1932, her 14-hour journey ended abruptly when she was forced to bring her Lockheed Vega 5B plane down in the Gallagher family's field at Ballyarnett, on the northern edge of Derry.
- She stayed the night with the Gallagher family, before traveling on to London, and then heading back to the US.
- Mrs Gallagher told the BBC in 1935 when Ms Earhart landed, the only thing she wanted was a telephone to tell her husband she had landed safely.
- Earhart later wrote that having landed without any money, Mr Gallagher, "owner of the field in which I landed, assured me, however, that I had no occasion to worry about money 'as we will see you through'".
Clare grew up hearing the story of that historic day on the family farm.
Her grandfather, also called Robert, was among the first to greet the celebrated US women pilot at Ballyarnett.
Then aged just nine, he would later often tell Clare of the day Ms Earhart came.
"It was a very, very surreal moment," Clare tells BBC News NI.
"Even just seeing the plane was a massive thing at the time, let alone the fact it was being flown by a woman."
As a child, Clare would become aware of the "huge significance of that day".
One of her daughters is named Amelia - "we wanted a name that really meant something to the family," she says.
Her family, she adds, have always done all they can to "promote the link with Amelia Earhart in any way they could".
The STEM challenge is a way of bringing together her family's story, aviation and Derry's history, with her passion for STEM subjects.
It's "bringing Amelia Earhart to a whole new generation," she says.
On Friday, STEM students from across Northern Ireland gathered at Ulster University's Magee campus to design and build their own model aeroplanes.
The competition's main prize will see winning pupils retrace Ms Earhart's flight path in a helicopter ride across the Derry skies.
Organised by the the Amelia Earhart Legacy Association, other events of the Amelia Earhart 90th Anniversary Arts Festival include a vintage ball in the city's Guildhall, the unveiling of a new mural in the Galliagh area of the city, and a vintage fashion show.
A walking tour will retrace Ms Earhart's footsteps during her unexpected visit to the city.
On Saturday, radio operators from around the world will share the Earhart story.
The North West Amateur Radio Club plans to transmit from the field where Earhart landed.
Among others, they will connect with the Amelia Earhart Memorial Airport in her hometown in Atchison, Kansas, and to Harbour Grace, the transatlantic flight's Canadian starting point.
Light aircraft from Eglinton Flying Club will take to the skies as part of the celebrations to mark the 90th anniversary.
On Sunday, 'Amelia's Story', the new multimedia dance production from Greater Shantallow Community Arts, has its premiere.
Nicole McElhinney, co-founder of the Amelia Earhart Legacy Association, says the significance of the Derry landing continues to resonate.
"When Amelia landed here, no one had ever seen a woman driving a car, let alone flying an airplane or wearing trousers," she says.
"Her fearless spirit was revolutionary, particularly for women, and continues to be an inspiration around the world."
The association will be joined at the festivities by a number of guests travelling from Atchison.
"We are honoured to return to Derry for this extraordinary 90th anniversary celebration hosted by our transatlantic partners at the Amelia Earhart Legacy Association in Derry," Karen Seaberg, of the Amelia Earhart Hangar Museum says.
"We share a commitment to preserve Earhart's legacy to defy the odds and pursue her dreams that changed aviation forever."
After completing her transatlantic challenge, Amelia Earhart became the first person to fly across the Pacific.
In 1937, Earhart set herself the challenge of being the first woman to fly around the world.
This challenge, however, would prove too great, and she disappeared after taking off from Lae, Papua New Guinea, bound for Howland Island in the middle of the Pacific Ocean.
A rescue attempt lasted 17 days and scoured more than 250,000 square miles of ocean, but she was never found.
Earhart remains a household name across the world, and an airport in her home state of Kansas was named in her honour, as well as an airport lounge at City of Derry Airport.
The Earhart museum is due to open next year in Kansas.