In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.

[Q]: Context: The Melkite Greek Catholics and the Greek Orthodox, tend to focus more on the Greco-Hellenistic heritage of the region from the days of the Byzantine Empire Link Information: none Answer: none
[A]: Of the two groups that focus on the Greco-Hellenistic heritage of the region, which has a larger congregation?


[Q]: Context: He fought in Operation Barbarossa, the German invasion of the Soviet Union, and claimed his first aerial victory on 8 August 1941. Link Information: none Answer: none
[A]: How many days did Operation Barbarossa last?


[Q]: Context: Inspired by the rioting in Copenhagen that followed the destruction of the Ungdomshuset(Youth House), Link Information: Although the earliest historical records of Copenhagen are from the end of the 12th century, recent archaeological finds in connection with work on the city's metropolitan rail system revealed the remains of a large merchant's mansion near today's Kongens Nytorv from c. 1020. Excavations in Pilestræde have also led to the discovery of a well from the late 12th century. The remains of an ancient church, with graves dating to the 11th century, have been unearthed near where Strøget meets Rådhuspladsen.

These finds indicate that Copenhagen's origins as a city go back at least to the 11th century. Substantial discoveries of flint tools in the area provide evidence of human settlements dating to the Stone Age. Many historians believe the town dates to the late Viking Age, and was possibly founded by Sweyn I Forkbeard. 
The natural harbour and good herring stocks seem to have attracted fishermen and merchants to the area on a seasonal basis from the 11th century and more permanently in the 13th century.  Answer: 900
[A]:
How old is the place that had riots after the destruction of the Ungdomshuset?