The science of food preservation isn't the most appetizing topic, but in this case, it's pretty neat.
A team of food scientists found a way to slow down the process of decay in sandwiches. Taking inspiration from preserved jams, they've added ingredients with water-retaining properties, such as honey, sugar and salt, in order to help keep moisture in and bacteria out. Any moisture or bacteria that remains gets trapped by a packet of iron shavings and transformed into a layer of rust.
Years later, the sandwich is, well, still a sandwich.
"It's definitely the best two-year-old sandwich I've ever had," one soldier told BBC. "It's better than a lot of new ones I've had, too."