The Planck length is a fundamental unit of measurement in physics, defined as approximately 1.6 \times 10^-35 meters. It is considered the smallest possible length scale in the universe, below which the conventional laws of physics may not apply. This concept arises from the combination of three fundamental constants: the speed of light, the gravitational constant, and Planck's constant. At the Planck length, quantum effects of gravity become significant, leading to theories that attempt to unify quantum mechanics and general relativity. It is a key concept in the field of quantum gravity and helps scientists explore the nature of space and time at the most fundamental level.