The theory of Pangaea was that the continents were once together and then were drifted apart due to plate tectonics.
Alfred Wegener, a German scientist in the early 1900's.
Alfred Wegener
Yes, there are a number of proofs: 1. Continents have a puzzle like fit 2. Glacier marks found in Antarctica are found pointing in the same direction in areas including South Africa and Southern...
continental drift