The Legend of Monarch Butterflies:

Monarchs spend their winter in Pacific Grove, California. Then they fly 2,000 miles north into Canada to spend their summer, where they breed and die. Their offspring return to Pacific Grove each fall, to the same forest, to the very same trees. The migration of salmon or geese is amazing, but we can imagine their being guided along familiar paths by their memory, ocean currents, or the stars. Monarch butterflies also know exactly where they are going. However, it is to a place they’ve never been.

Adapted from Charles Kuralt