4. Spain: 52.7 million visitors
Spain is one of the most preferred destinations to spend summer holidays and this is quite understood by seeing the number of tourists from British Isles, France, Central Europe and Scandinavia flowing into the nation, during this season. Madrid and Barcelona, the two largest cities in Spain are the leading city destinations in Spain and UNESCO has also declared thirteen Spanish cities as World Heritage cities. The country has some of the best nightlife in the world, which draws both foreigners and locals.