Despite calmer stretches like the one photographed above in summer 2008, the Congo is the world's highest-volume white-water river, according to Trip Jennings
, a National Geographic Expeditions Council
As part of a 2008 expedition, Jennings and his team of kayakers navigated the churning river's powerful whirlpools.
"The six of us were tossed about like pool toys in a hurricane," Jennings said. "Giant whirlpools threatening to suck us under spawned without warning, and oceanlike breaking waves crashed on us from all sides."
The kayakers started in the Democratic Republic of the Congo's capital city of Kinshasa
and ended 85 miles (137 kilometers) downstream in Pioka--marking the first time this stretch of the river had been run successfully.
Their boats were equipped with echo sounders to collect data on the river's depth, revealing that the Congo may be the world's deepest river--one section reached a record 755 feet (230 meters).
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Photograph courtesy Todd Wendel/National Geographic Television