For the first time ever, physicists have managed to take a photo of a strong form of quantum entanglement called Bell entanglement—capturing visual evidence of an elusive phenomenon which a baffled Albert Einstein once called 'spooky action at a distance'. Two particles which interact with each other—like two photons passing through a beam splitter, for example—can sometimes remain connected, instantaneously sharing their physical states no matter how great the distance which separates them. This connection is known as quantum entanglement, and it underpins the field of quantum mechanics. Einstein thought quantum mechanics was 'spooky' because of the instantaneousness of the apparent remote interaction between two entangled particles, which seemed incompatible with elements of his special theory of relativity. Later, Sir John Bell formalised this concept of nonlocal interaction describing a strong form of entanglement exhibiting this spookiness. Today, while Bell entanglement is being