7.7M views · 49K reactions | #OnThisDay in 1912, Alfred Wegener presented a radical idea: all seven continents were once a single landmass. He theorized that the original continent, Pangaea, slowly drifted apart over millions of years. His theory of continental drift was met with skepticism, but later confirmed by plate tectonics in the 1960s. Learn more: https://www.aps.org/archives/publications/apsnews/201901/history.cfm #PhysicsHistory | American Physical Society | Facebook