Context: In 1983 the historic old town in the centre of Bern became a UNESCO World Heritage Site. Bern is ranked among the world’s top ten cities for the best quality of life (2010).

Question: Where is the UNESCO World Heritage Site?
Answer: centre of Bern

Question: Where does Bern rank for top cities for the best quality of life?
Answer: top ten

Question: When did the centre of Bern become the UNESCO World Heritage Site?
Answer: 1983