EXPEDITION IMPOSSIBLE - "And Then There Were Four" - After nine grueling weeks, the final four teams are put to the test in the last stage of "Expedition Impossible." Through lakes and deserts, on horses and camels, teams find themselves in the ancient city of Marrakech, where one team will claim the ultimate victory, on the exciting season finale of "Expedition Impossible," THURSDAY, AUGUST 25 (9:00-10:00 p.m., ET) on the ABC Television Network. (ABC/GILLES MINGASSON)