Tumbling from the highlands of southeastern Angola, the Chobe River marks the boundary between Namibia and Botswana before it flows into the Zambezi near Victoria Falls. About as wild as a river can be in the 21st century, the Chobe is flanked by national parks and reserves rich in African flora and fauna. Most of the overnight cruises originate in Kasane (Botswana) and head upriver into a land where elephants are still more numerous than people.