Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.

Context : Trace of Stones (German: Spur der Steine) is a 1966 East German film by Frank Beyer. 
Answer : Spur der Steine
The Trace of Stones is based upon what?

Context : Swiss Private Aviation AG was a fully owned subsidiary of Swiss International Air Lines providing executive jet services as well as aircraft management and commercial charter services on behalf of its parent company. 
Answer : Swiss International Air Lines
What is Swiss Private Aviation's parent company?

Context : Storstrøm Bridge (Danish, Storstrømsbroen) is a road and railway arch bridge that crosses Storstrømmen between the islands of Falster and Masnedø in Denmark. 
Answer : Storstrømmen

Over which river does Storstrøm Bridge cross?