Rivers are the lifeblood of continents, and the world's longest is traditionally the Nile, flowing about 6,650 kilometers northward through northeastern Africa to the Mediterranean Sea, though some measurements suggest the Amazon may actually be longer. By volume, the Amazon is unrivaled, discharging roughly 209,000 cubic meters per second into the Atlantic—more than the next seven largest rivers combined. Other notable rivers include the Yangtze, the longest in Asia at about 6,300 kilometers, which flows entirely within China from the Tibetan Plateau to the East China Sea; the Volga, the longest in Europe at about 3,530 kilometers, emptying into the Caspian Sea; and the Missouri, the longest in North America at about 3,767 kilometers, often considered part of the larger Mississippi-Missouri system that runs about 6,275 kilometers.
A few rivers are notable for unusual characteristics. The Danube, the second-longest river in Europe at about 2,850 kilometers, is famous for passing through or bordering four national capitals: Vienna, Bratislava, Budapest, and Belgrade. The Nile not only shapes the geography of northeastern Africa but also gives rise to one of the world's great deltas where its sediment spreads into the Mediterranean. The Amazon, beyond its record discharge, also drains the largest rainforest on Earth.
Lakes range from freshwater giants to saline extremes. Lake Superior in North America is the largest freshwater lake by surface area, about 82,100 square kilometers, and is one of the five Great Lakes—Superior, Michigan, Huron, Erie, and Ontario, often remembered by the acronym HOMES—which together hold about 21 percent of the world's surface fresh water. Lake Baikal in Siberia is the deepest, plunging about 1,642 meters, and contains roughly 20 percent of the world's unfrozen surface fresh water. Lake Victoria is Africa's largest lake by area at about 68,800 square kilometers, and Lake Titicaca, on the border of Peru and Bolivia, is the highest navigable lake in the world at about 3,812 meters above sea level. The Dead Sea, by contrast, sits at the opposite extreme, about 430 meters below sea level—the lowest land-based elevation on Earth.