Year after year, millions of North American monarch butterflies make their way on a 3,000-mile journey from locations across Canada and the United States to winter in Mexico, where they gather in oyamel fir trees in the states of Michoacán and Mexico. In recent years, scientists have noted a sharp decline in the number of monarchs making this amazing pilgrimage, prompting U.S. President Barack Obama, Mexican President Enrique Peña Nieto and Canadian Prime Minister Stephen Harper to establish a new group dedicated to conservation of these miraculous creatures.