Superconductivity is a phenomenon where certain materials can conduct electricity without any resistance when cooled to very low temperatures. This means that electrical current can flow through these materials indefinitely without losing energy, making them highly efficient for various applications. The discovery of superconductivity was first made in 1911 by Heike Kamerlingh Onnes, who observed this effect in mercury. Superconductors are used in technologies such as MRI machines and particle accelerators, and they have the potential to revolutionize power transmission and magnetic levitation systems.