3. Harvard University, Cambridge, United States

Think of a New England, Ivy League university and you probably picture a group of imposing red-brick buildings surrounded by green lawns and trees that become a riot of reds, browns, oranges and yellows in autumn. The one that started it all was Harvard, founded in 1636 and the oldest American university. Central to its campus is Harvard Yard with its freshman dormitories, libraries and halls surrounding leafy courtyards. In snowy winter weather these courtyards are covered in white.