Monarch Butterfly Biosphere Reserve, Mexico
This reserve is located approximately 100 km northwest of Mexico City. The area has rugged mountainous terrain surrounded by dense forests. The core protection area covers 136 km2, and including the buffer zone, the reserve covers an area of 563 km2. In the autumn, millions to billions of butterflies return from across North America and gather on orange branches in the small woodlands in the forest reserve. In the spring, the butterflies began another 8-month migration to eastern Canada. During this period, four generations of butterflies complete their life-cycles.