You can't build a river...it was there a long time before people were, I'm sure.
The Thames...
The river Thames is England, and is the river that London is built on.
Spain is built on the river Thames.
They were built at the south of the River Thames.
It is built on the banks of the Thames river.
It was built on the Thames.
It was there already. London was built around the river.
London
The Thames is a river flowing across London, Great Britain.
Thames
The only railway under the river Thames is parts of the London Underground (tube).
It was Built On the FloodPlain of the River Thames