Lake Superior is the largest freshwater lake on Earth by surface area.
It is also the second-largest lake on Earth after the Caspian Sea. Lake Superior's surface area is 82,000 km2 (31,700 sq mi). Its maximum length is 560 km (350 mi), and maximum width 260 km (160 mi).
As early as the Stone Age, people were settling in the Nile Valley.
The largest population center was north of present-day Aswan. Ancient Egyptians sang a hymn to the Nile, thanking the river for being and bestowing wealth on their country.
In 2011, researchers discovered two new species of freshwater stingrays in the Amazon River.
The Heliotrygon (rosai and gomesi), commonly referred to as the Pancake stingrays, is the first new genus of stingrays from the Amazon described since 1987.
