Question: What is the longest river in Europe? Answer
The Volga is the longest river in Europe, stretching for a length of 3,531 kilometers (2,194 miles). It flows through central Russia and empties into the Caspian Sea.
Complete the following task based on the instruction and optional input provided.### Instruction:
Question: What is the longest river in Europe? Answer

### Output:
The Volga is the longest river in Europe, stretching for a length of 3,531 kilometers (2,194 miles). It flows through central Russia and empties into the Caspian Sea.