Modern Physics began at the turn of the 20th century when Max Planck invented the idea of the quantum. The world hasn't been the same since. Albert Einstein constructed the special theory of relativity five years later. The nucleus was discovered and investigated. The states of the atom were unraveled by Niels Bohr. Light was understood to be made of waves, then particles, and then, with the development of Quantum Mechanics, both at the same time. Werner Heisenberg proposed the Uncertainty Principle, and Erwin Schrödinger thought about cats that could be alive and dead simultaneously.
