Could be a dam, but perhaps you're thinking of "levee."
a levy
A wall built without any mortar
A Levee
levees are two parallel wall built at both sides of a river to prevent river overflowing
A cliff
a dam
a levy
No, it was built to keep the Huns out of China
To keep people in.
Berlin Wall
they both built the walls to keep them out with a wall
the great wall of china
Hadrian's wall was built to keep the Scots out of England many of centuries ago
The great wall was built to keep the mongol hoards out of china.
No. The Great Wall of China was built as a defensive barrier against invading armies.
they built the wall with rocks and earth to withstand heavy attacks.
to keep the rabbits out