A tunnel
The Amazon River.
The Chang Jiang River, also called the Yangtze River, flows through China and empties into the East China Sea. At 3,915 miles long, it is the longest river in Asia and the third longest in the world.
The Equator does indeed run across the large country in Africa which was called Zaire for about 20 years, but is now called Democratic Republic of Congo. The big river running through that country is called the Zaire River or the Congo River.
There are two rivers that are called Red River in the United States. One of them flows between the states of Minnesota and North Dakota. The other Red River flows through the states of Texas, Oklahoma, Arkansas, and Louisiana.
It is formed by water hitting both sides for years until there is no more land there and water can get through from both sides.
It is a tunnel.
Dam
it could be a valley or a gorge
gorge
Channel (Valley)
The Molonglo River was dammed to create the artificial lake Lake Burley Griffin.
it could be a valley or a gorge
An artificial river is called a canal, It is a Waterway that was created by human hands or machinery, usually to divert the water away from its previous course.
The marshy inlet of a river or lake is called a bayou. The name for an artificial waterway is a canal.
The mouth of a river is the open space at the end of a river allowing passage. The mouth of a river, sometimes called a delta, is the point at which the river ends and the water flows into the sea.
It is called the Seine River.
river through gobii think the Huang river