Top 10 rivers facts

It doesn't have an outlet to the sea. Discharging to an endorheic basin, the Okavango does not have an outlet to the sea. Instead, it empties into a swamp in the Kalahari Desert, known as the Okavango Delta or Okavango Alluvial Fan.

None. The Portuguese were the Europeans who encountered Guanabara Bay on January 1,1502. They took it for a large river, which they named "Rio de Janeiro" ("January River"). Later it was discovered, that the presumed river was in fact a gulf, but the name remained.

In Venezuela. Catatumbo lightning is an atmospheric phenomenon in Venezuela. It occurs only over the mouth of the Catatumbo River where it empties into Lake Maracaibo. The phenomenon is characterized by almost continuous lightning and occurs during 260 nights a year, 10 hours per day and up to 280 times per hour. It has been known for centuries as the Lighthouse of Maracaibo, since it is visible for miles around Lake Maracaibo

In Thailand. River Kwai in Thailand today, but there was no such river when the "bridge on the River Kwai" was created. The movie tells a fictional story, and the film crew built a wooden bridge on the Mae Klong river. This part of the river was then renamed Khwae Yai to bring geographical fact more in line with the movie.

In Turkey. The river modern name is Karamenderes. It flows entirely within the Turkish province of Çanakkale, in the Marmara region.

Missouri. The Missouri River is the longest river in North America. Having 2,341 mi (3,768 km), it is longer than the Mississippi (2,202 mi 3,544 km). When combined with the lower Mississippi River, it forms the world's third longest river system, after the Nile and Amazon.

Varanasi. Hindus believe that bathing in the Ganges remits sins and that dying in Varanasi ensures release of a person's soul from the cycle of its transmigrations. Those who are lucky enough to die in Varanasi, are cremated on the banks of the Ganges, and are granted instant salvation. Thus, many Hindus arrive here for dying.

Water salinity. Launched June 10, 2011, Aquarius is NASA’s first satellite instrument specifically designed to study the salt content of ocean surface waters. The complete first year dataset of NASA's Aquarius instrument reveals seasonal changes in the Amazon River's plume. Depending on the prevailing currents, the river's freshwater outflow heads east toward Africa or bends up north to the Caribbean.

Congo is the deepest river in the world, reaching 250 meters of depth in the deepest trench. It is followed by Yangtze (200m) and Danube (178m). The maximum depth of the Amazon River is 80m.

In Iceland. Dettifoss is situated on the Jökulsá á Fjöllum river, which flows from the Vatnajökull glacier and collects water from a large area in Northeast Iceland. The falls are 100 metres (330 ft) wide and have a drop of 45 metres (150 ft) down.