Trevi fountain is among the most visited tourist spot in rome.I never imagine the crowds is everywhere u can't even hardly find the good spot for taking a pictures. We went there in night time still that massive crowds do exist. Second time around i walk up early in the morning which most people advised to do so but then the problem is those shops an building was covering the beauty of that fountain so either which time you went just embrace that overwhelming crowds and enjoy the most of it don't freak out.