The seaport city of Alexandria, with a population of more than 3.5 million, is built primarily on a sandy strip of land between the Mediterranean Sea and Lake Mareotis. An industrial and commercial city, Alexandria anchors the western extent of the large Nile River Delta. Although most of the city infrastructure is not visible, some of the large modern harbor facilities, including a breakwater structure, are discernible in the small bay. The unusual tan water body southwest of the port facilities is possibly a holding pond for industrial effluents. A narrow band of darker substance in the water current appears to be flowing toward the east, and farther offshore, an interesting light blue turbidity indicates water color boundaries along this part of the Mediterranean Sea. A series of canals and roadways appears within the darker green of the fertile, intensively cultivated and irrigated, agricultural Nile River Delta. Circular field patterns southwest of the city indicate that center-pivot irrigation is being used in addition to irrigation from ditches and canals. The smaller, highly reflective areas scattered among the irrigated farmland are villages and cities.