Christie is pictured with Max Mallowan in 1931 celebrating their marriage aboard a Nile steamer in Egypt. It was on one of her trips around the country that Christie was inspired to write Death on the Nile.
In another image the world-famous author can also be seen with Max and Leonard Woolley in Al Mina, Syria, in the 1930s.
Woolley was a famous archaeologist who Max worked for in the 1920s and 30s.
It was on one of Leonard and his wife Katherine's digs that Agatha first met lover Max.
The photos will be on show in an exhibition about the most widely published author of all time - opening in Torre Abbey, Devon, this month.
A Christie Archive Trust spokesperson said: "Both shots have previously been published but not at all widely.
"There are many unseen photos and objects at the exhibition itself.
''It is impossible to say when or where stories such as Death On The Nile were first imagined - she had been to Egypt in 1907 as well.''
This latest exhibition uses her own words, photographs, letters and poetry to tell the story of her second marriage to archaeologist Max Mallowan.
The result is an intimate glimpse into her extraordinary adventures to the Middle East.
The author famously married Mallowan on 11 September 1930 at St Cuthbert's Church on Edinburgh’s Lothian Road after divorcing her first husband, Colonel Archibald Christie.
Local councillor Mike Morey said: "Torre Abbey is the first place in the world to host this brand-new exhibition, which is a real coup for Agatha Christie's hometown.
"I can't wait to see this fascinating insight into the author's travels, and I want to thank Agatha's grandson, Mathew Prichard for working with us over lockdown to create something so enthralling and timely.
"At a time when many of us have been unable to travel, due to the restraints of the last 18 months, it is going to be really special to learn about Agatha Christie's inspirational travels 90 years ago."
Mathew Prichard, Agatha Christie's grandson said: "What better place to launch a new Agatha Christie exhibition than at Torquay during the Agatha Christie festival?
"This new exhibition covers the years after 1930 and my grandmother's second marriage to archaeologist Max Mallowan.
"It is a unique bird's eye view of one of the most affectionate and productive relationships of the twentieth century."
John Curran, author and Agatha Christie expert said: "This is a not-to-be-missed exhibition of an Agatha Christie her fans rarely see - Agatha the Traveller, the Photographer, the Archaeologist."
Agatha Christine: Destination Unknown. A journey in poetry, pictures and archaeology is included with museum entry and runs from September 11 to November 28, while the International Agatha Christie Festival runs from September 11 to September 18.
The exhibition is one of a number of events taking place at Torre Abbey.