The glacier-fed Rio Santa Cruz drains the Fitzroy Range of the Andes via Lago Viedma and Lago Argentino and flows for 385km east to the Atlantic Coast. In 1834 Charles Darwin and the crew of 'HMS Beagle' anchored at the mouth of the Rio Santa Cruz and sent a party upriver for sixteen days to explore the area. The Rio Santa Cruz provides water for irrigation and hydroelectric power. Between El Calafate and Tres Lagos, a distances of 130km, only the first 30km of the road east of El Calafate were paved. 30 km east of El Calafate the northbound Ruta 40 is gravel for the 600km to Perito Moreno. Ruta 40 crosses Rio Santa Cruz between the turnoff and Tres Lagos. Patagonia encompasses an area of roughly 900,000 square kilometer, but has only 3% of Argentina's population of about 40 million. Most of the 3% are concentrated in Comodoro Rivadavia and Rio Gallegos along the Atlantic Coast. This picture was taken on 21 December 2003. Thank you for viewing, commenting, and favs, Sig... I will comment soon!!