This theory, which revolutionized our understanding of gravity, space, and time, is comprised of two parts:

* Special Relativity: Explains how space and time are relative to the observer's motion. It led to famous concepts like time dilation and length contraction.

* General Relativity: Explains gravity as a curvature of spacetime caused by mass and energy. It predicts phenomena like black holes and gravitational waves.

However, Einstein's contributions extend beyond relativity. He was also a pioneer in:

* The photoelectric effect: He explained how light can act as both a wave and a particle (photons), which paved the way for quantum mechanics.

* Brownian motion: He provided a theoretical explanation for the random movement of particles suspended in a fluid.

* Mass-energy equivalence: His famous equation E=mc² states that mass and energy are equivalent and can be converted into each other.

Overall, Einstein's work has had a profound impact on modern physics and our understanding of the universe. His name has become synonymous with genius, and his contributions continue to be studied and explored today.