The 'phenomenon' known as Iced Tea is really an American creation. This delightful beverage was in fact a response to an immediate need during the St. Louis World's Fair back in 1904.
English merchant Richard Blechynden was in charge of the tea pavilion at this world attraction. Richard realized that he was having a difficult time selling the hot stuff to fair attendees. He had a moment of epiphany and added ice to the brewed liquid and and ice tea as we know it was born. American's consumption of iced tea is far more than that of any other country in the world. 80% of the tea drunk in America is iced.
I am sure with the recent resurgence of more traditional forms of tea consumption in the United States that percentage will change, however Americans love their iced tea and the cold beverage shows no signs of slowing down.
Now what does the Louisiana Purchase have to do with this story? Well the actual celebration in St. Louis was in fact to commemorate the 100 year anniversary of the purchase and acquisition of Louisiana. The original name was the 'Louisiana Purchase Exposition'.