Background: 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: In what year was Bern ranked as one of the 10 best cities for their quality of life?
Answer:<extra_id_0>.
<extra_id_0> 2010<extra_id_1>