Every year, millions of tourists fly from central Mexico into the United States, first stopping in the deep American South and then continuing northward even into parts of southern Canada. How all of this is done without passports, customs agents or airplanes?
This is the annual journey made by monarch butterflies, one of the best-known and most beloved butterflies in North America.
The fact that the annual migration of these distinctive black and orange butterflies spans three countries and thousands of miles makes it an important and prolific pollinator over this large area.