Nowadays the factors of tourist interest in Italy are mainly culture, cuisine, history, fashion, architecture, art, religious sites and routes, naturalistic beauties, nightlife, underwater sites and spas. Winter and summer tourism are present in many locations in the Alps and the Apennines, while seaside tourism is widespread in coastal locations along the Mediterranean Sea. Small, historical and artistic Italian villages are promoted through the association I Borghi più belli d'Italia (literally "The Most Beautiful Villages of Italy"). Italy is among the countries most visited in the world by tourists during the Christmas holidays. Rome is the 3rd most visited city in Europe and the 12th in the world, with 9.4 million arrivals in 2017 while Milan is the 5th most visited city in Europe and the 16th in the world, with 8.81 million tourists. In addition, Venice and Florence are also among the world's top 100 destinations. Italy is also the country with the highest number of UNESCO World Heritage Sites in the world . Out of Italy's 61 heritage sites, 55 are cultural and 6 are natural.