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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