Albert Einstein is also known as the father of Modern Physics. He had a dream of unifying a theory that explains macroscopic and microscopic. Although he was never able to achieve that dream even on his death bed.
Unification is the master equation that describes everything in the universe.
General Relativity is the geometric theory of gravitation. Einstein described general relativity to be the warps and curves of the universe. It also describes gravity and it's geometric property of spacetime.
Niels Bohr contributed to the idea of quantum mechanics. Quantum mechanics proves that everything is ruled by chance, meaning you can't know the outcome for certain. it describes the behavior of all the particles that make up the universe.
The four fundamental forces of modern physics include gravity, strong nuclear force, weak nuclear force, and electromagnetic force.
String Theory is also known as the theory of everything. It is the key to the world of the large and the world of the small. For a good amount of time in the late 1960's string theory was abandoned because physicists believed it had anomalies but they were wrong.