When we look at the world at the tiniest scales in the subatomic realm, things get weird—very weird. Welcome to the quantum universe, where particles can spin in two directions at once, observing something changes it, and something on one side of the galaxy can instantly affect something on the other, as if the space between them didn’t exist. Buckle up for a wild ride through the discoveries that proved all of this to be true and paved the way for the digital technologies we enjoy today—and the powerful quantum sensors and computers of tomorrow.