Scientists have pulled a 1,700-year-old egg from the ground at an archaeological dig, and found that it contains original the liquid and an air bubble inside, making it a unique find. The egg comes from Berryfields, an archaeological site near the English town of Aylesbury, which lies about 45 miles northwest of London, in Buckinghamshire, where there was human activity from the early Neolithic period to post-medieval times. 

“We were absolutely blown away when we saw the contents in there, as we might have expected them to have leeched out,” Edward Biddulph, senior project manager for Oxford Archaeology, which conducted the dig from 2007 to 2016, told the BBC.

The site yielded up items including a woven basket, pottery vessels, coins, leather shoes, animal bone, and, perhaps most surprisingly, a number of eggs, one of which the team was able to recover intact. (The others broke, resulting in predictably awful smells.) The experts believe it’s from a chicken. The liquid inside, likely representing yolk and albumen, was discovered upon submitting the egg to a micro CT scan. 

The archaeologists then consulted with Douglas Russell, senior curator of the collection of bird’s eggs and nests at London’s Natural History Museum, who pronounced the intact egg with liquid center the only known such egg in the world. 

Efforts are now underway to determine how scientists can use the egg in their research, as well as how to store it. 

“There is huge potential for further scientific research,” said Biddulph, “and this is the next stage in the life of this remarkable egg.”