For all cities with a population greater than one million, Barcelona is closest to Madrid and farthest from Auckland. The closest foreign city is Algiers and the farthest domestic city is Madrid. See below for the top 5 closest and farthest cities (domestically, internationally and by continent) and to see which cities, if any, Barcelona is the closest and farthest to. Filter to include all cities over 100k, 500k or 1 million in population.