In southeastern Chad, Zakouma National Park offers the chance to witness a miracle. The national park’s populations of wild elephants and rhinos had been all but wiped out before its management was taken over in 2010 by the public-private consortium African Parks. The elephant herd is now one of the largest in Africa, and the rhinos are also making a comeback. Last year, African Parks airlifted in a starter herd from South Africa, marking the long-awaited return of the rare black rhino. A U.S. advisory warns travelers against visiting Chad because of the risk of terrorism and other dangers, but the park’s conservation achievement is still one for the books. —Aryn Baker