This equation is used to analyse everything from the shape of a soap bubble to the trajectory of a rocket around a black hole.
"More than just an equation, it's actually a recipe to generate an infinite variety of possible physical laws," says Andrew Pontzen of University College London in the UK.
Despite its many applications, the equation is "deceptively short and simple," says Pontzen.
"The way that all classical physics can be expressed and understood within a single framework like that helps reveal deep links between seemingly different phenomena."
Read more: What is the most beautiful equation?