For 10 consecutive years,Barcelona has appeared first in survey of European cities that asks which city offers the best quality of life tp its citizens. So what makes Barcelona , one of the world's most-visited cities,one of the best places to live ? Residents and visitors to the city point out several aspects relating to everyday life,including the friendliness of the people , the efficiency of the public transportation system,safety,a very rich cultural heritage,and the high quality of education