secret safari; Two new properties combine the ultimate in private luxury with a forward-thinking philanthropic spirit.( Jan Bonde Nielsen's Oldonyo Laro)

Byline: Richard Alleman

Encompassing 60,000 acres within the Nguruman Wildlife Sanctuary of Southern Kenya's Great Rift Valley, Oldonyo Laro is the spectacular ranch of Danish tycoon Jan Bonde Nielsen, whose guests have included George Soros and the Danish and Dutch royal families. Now he is opening his exclusive world, on a limited basis, to outside groups of up to fourteen. Staying in exquisitely outfitted safari tents, guests have the run of the property, which boasts a pool, a gym, a thatched dining pavilion, waterfalls, and game reserves harboring wildebeests, leopards, and lions. For those seeking adventure farther afield, the ranch has a pair of helicopters, as well as several Cessnas, ready to take you to legendary East African spots such as the Serengeti (especially awe-inspiring during migration season), Mount Kenya, and the Chalbi Desert. For all these destinations, the Oldonyo Laro staff goes ahead by land to set up comfortable mobile campsites. In charge of everything at Oldonyo Laro-the excursions, visits to Masai villages, perhaps lunch and a chat with anthropologist Richard Leakey-is one of Kenya's top guides and experts, Peter Silvester. The price of having your own private Africa is a hefty $250,000 a week-but the good news is that all the profits (after operating expenses have been deducted) go to regional educational and environmental charities. (203) 542-0567; jour neysbydesign.co.uk.

In the foothills of Mount Kenya, the new Sanctuary at Ol Lentille is another private compound offering the ...