One of the Eight New Natural Wonders
The three core zones of the Monarch butterfly biosphere reserve protect eight overwintering colonies of the monarch butterfly in the oyamel fir forests of central Mexico. Perhaps a billion monarch butterflies overwinter here in close-packed clusters every year after a 3,500-4,500km journey. Witnessing this unique phenomenon is considered to be an exceptional experience of nature.
I wonder which ones are 21 and 24?
