How well can we predict the future? Prior to the quantum mechanical revolution, the universe was believed to be deterministic and that if we could know all the initial properties of a system, the future, just like the past, would be certain. Quantum mechanics has given us insights about the unpredictability of events at an atomic scale. However, even at the macroscopic scale, nonlinear deterministic systems are unpredictable as any tiny change in the initial condition can lead to different final states – which is now known as the chaos theory. In this talk, I take you on a tour of this branch of mathematics and physics. A prior knowledge of the field is not required. I shall start by discussing the ubiquity of chaotic systems, starting from dripping faucet to boiling water. This will be followed by a brief discussion on the universal properties of such systems. Finally I will discuss how one can utilize the concept of chaos theory for practical purposes such as defibrillation of the heart and blood diagnosis.