A dense plume of tan dust blows out of the Great Sand Sea of northeastern Libya and northwestern Egypt in this true-color Aqua MODIS image from February 28, 2005. The plume extends out into the Mediterranean Sea, hiding much of the coastline and casting a thin veil over the deeply blue water. East of the dust plume is the lotus-shaped Nile River Delta - a fan of lush green marking one of Egypt's most fertile and populous regions. It is in this delta that the majority of Egypt's large cities, both modern and ancient, are located. Just off the Delta's coast is a delicate blue-green halo of sediment, while to the west is a more intense bright blue halo that could be the result of tiny marine organisms (like phytoplankton and algae).