On which river does Berlin stand?

The Elbe

The Spree.

Going once, going twice ...

I will raise it to two Sprees

"The Spree, the Havel and another three rivers, as well as six channels flow through the town, creating over 180 km waterways plus more than 3000 hectares of lakes."

"The Havel, Oder, Spree and Elbe rivers, along with more than 3,000 thousand lakes and numerous canals make the region Brandenburg around Berlin a paradise for all acqua-philes and water sport enthusiasts."

https://en.wikipedia.org/wiki/Category:Rivers_of_Berlin