Continents were once thought to be static—locked tight in their positions in Earth's crust. Similarities between distant coastlines, such as those on opposite sides of the Atlantic, were thought to be the work of a scientist's overactive imagination, or, if real, the result of erosion on a massive scale. This interactive activity adapted from NASA shows the position of Earth's continents on 11 massive tectonic plates and illustrates the motion of these plates relative to one another.
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