No one knows exactly how life began, but scientists believe it started over 3.5 billion years ago—long before plants, animals, or even oxygen. The first living organisms likely emerged from a mix of water, simple molecules, and energy.

Some theories suggest life began in a “primordial soup” struck by lightning. Others point to deep-sea vents, where heat and minerals may have powered the first reactions. The most intriguing idea? That RNA molecules—capable of both storing information and copying themselves—were nature’s first spark of life.

From chemistry to cells, life may have started as nothing more than a lucky chain reaction.