Transcription: The length of a river can be estimated in different ways, since the location of its source and especially its mouth are not undisputed facts. According to most calculations, the longest river on the planet is the Nile at 6700 km. But the Amazon would be almost 7000 km long if one took into account the Andean rivers that it flows from. Usually, lakes are of glacial origin. This is the case for most lakes in Europe and North America. Some lakes, however, such as those in the Grand Rift region in Africa and Lake Baikal in Asia, are of tectonic origin. There are some 20 lakes in the world with an ...
(.mp3)