Monarch Butterfly Biosphere Reserve

Every autumn, monarch butterflies pour out of North America and converge on a few patches of fir forest in the mountains of Michoacán, roughly 100 km northwest of Mexico City — millions upon millions of them, enough to bend branches and turn whole trees orange. From these 56,259 protected hectares they launch a migration spanning four generations and reaching as far as eastern Canada. The reserve became a UNESCO World Heritage Site in 2008.