Three hundred years ago, wealthy young Englishmen began taking a post-Oxbridge trek through France and Italy in search of art, culture and the roots of Western civilization. With nearly unlimited funds, aristocratic connections and months (or years) to roam, they commissioned paintings, perfected their language skills and mingled with the upper crust of the Continent. No one knows who came up with it, but their adventures soon had a perfectly appropriate name: the Grand Tour.
Source: wiktionary