Olduvai Gorge, Tanzania

You'll be roughing it in your tent and sleeping bag in this magnificent Tanzanian landscape, but you'll also be walking in the footsteps of Louis and Mary Leakey as you search for artifacts of early hominids and later Stone Age cultures. The effort is essential to continued discoveries, as erosion is washing away numerous artifacts. The archaeology party camps and dines in the historic Leakey camp, and spends days excavating and screening for fossils; there's time to venture into Ngorongoro Crater and the Serengeti National Park, and visit the Maasai. Three 14-day trips are scheduled from May to September; the requested contribution is $2,850.