Traditional fishing boat were used for war and trade. Some ancient vessels were propelled by either oars or sail, depending on the speed and direction of the wind (see trireme and bireme). The Chinese were using sails around 3000 BC, of a type that can still be seen on traditional fishing boats sailing off the coast of Vietnam in Ha Long Bay. A jangada is an elegant planked fishing boat used in northern Brazil. It has been claimed the jangada dates back to ancient Greek time. It uses a triangular (lateen) sail, which allows it to sail against the wind. A felucca is
Flooding of the Nile Flooding of the Nile The flooding of the Nile () has been an important natural cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as "Wafaa El-Nil". It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, The Martyr's Finger (, ). Ancient Egyptians believed that the Nile flooded every year because of Isis's tears of sorrow for her dead husband, Osiris. The flooding of the Nile is the result of the yearly monsoon between May and