Cellular Automata are mathematical models used to simulate complex systems through simple rules. They consist of a grid of cells, each of which can be in a finite number of states, such as "on" or "off." The state of each cell changes based on the states of its neighboring cells according to predefined rules, allowing for the exploration of patterns and behaviors over time. These systems can be one-dimensional or two-dimensional and are often used in fields like computer science, physics, and biology. A famous example is Conway's Game of Life, which demonstrates how simple rules can lead to intricate and unpredictable patterns.