Little-known fact: Most earthworms in U.S. soil aren't native. They came in European ships with the first colonists in the 1600s. Over time, the European worms took over the upper layers of the soil and drove native earthworms underground, launching a 400-year invasion that's still going on today.
Created by homeschool students Molly Enriquez, Joe Giardina and Anne Marie Nolan at the Smithsonian Environmental Research Center.
