Initial herds of wildebeests and zebras arriving at Sand River in Tanzania's Serengeti National Park before crossing onto Masai Mara on the Kenyan side during the start of the spectacular annual migration.

One of the "Seven New Wonders of the World", more than two million heads of mainly wildebeest and zebra migrate from Serengeti National Park in Tanzania to the greener pastures of Masai Mara National Reserve in Kenya from July through October every year.