Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, approximately 335 to 175 million years ago. It formed by the gradual collision and merging of earlier landmasses and included nearly all of Earth's continental crust. Pangaea began to break apart during the Jurassic period, leading to the formation of the continents as we know them today. The concept of Pangaea is crucial for understanding plate tectonics and the geological history of our planet.