Imagine that you are a member of an alien group and you have been sent to the planet earth to find out more about that planet. Your UFO landed in the safest region which is the desert. The first thing that grabbed your attention on landing there was the monumental pyramids standing there. Coincidentally the energy in your spacecraft also finished when you got there. However you know that there is an ancient sphinx artifact hidden somewhere there and it could restore the energy supply of your spacecraft. You now have no choice but to find that particular artifact by exploring the dessert pyramids because only then you could fly back home.