I want to travel to Europe in August. Which cities are least busy?

Sarajevo for sure fits what you want! It is in Bosnia and Herzegovina , located in Europe. The culture in Bosnia is great and the people are nice. Its not busy in tourism only on main attractions like the Bosnian Pyramid and etc. There is no beaches so you don't have to worry about that. There is much to do in Sarajevo and if you go, trust me you wont regret it! :)