This bread is a blast from the past.
Scientist Seamus Blackley says he used ancient yeast from 4,500 years ago to bake a loaf of sourdough bread.
Blackley, who is also famous for being the brainchild of the Xbox game console, says he extracted the yeast sample from a piece of ancient Egyptian pottery.
He shared the results of his experiment in a viral Twitter post.
He says the bread tasted "richer and sweeter" than normal sourdough.