Ciudad Guayana lies on the south bank of the Orinoco River, the second largest in South America, at its confluence with the Caroní River (lower left). Islands have developed in the Orinoco in a wide spot opposite the city (upper left). Guayana is one of the newest cities in Venezuela, constructed in 1961 as a new economic center for the interior of Venezuela, especially for major industries such as iron, steel, and aluminum. The city stretches 40 km (24 mi) along the south bank of the Orinoco and is one of Venezuela's largest. A low barrage (lower left) dams the Caroní as a water supply for the city. The Orinoco River is muddy brown, carrying sediment produced by erosion of the Andes Mountains far to the southwest. By contrast, the Caroní is clear blue, as it drains the ancient landscapes of the Guyana Highlands, where erosion is much slower. A mixing zone can be seen in the middle of this image. The clear Caroní water produces a less muddy zone for tens of kilometers downstream of the confluence (this part of the Orinoco flows almost due east, left to right). Image courtesy of NASA.