It was the first seven-day event in the RacingThePlanet Series -LRB- also called the Four Deserts Race -RRB- : four foot races that each cross roughly 155 miles of four of the world 's great deserts -- the Gobi , the Sahara in Egypt , the Atacama in Chile and -LRB- by invitation -RRB- the Horseshoe Valley of Antarctica , near the Patriot Hills .