fentress architects became internationally recognized after designing the iconic dia (denver international airport), known not only for its unique, white canvas peaked roof suggesting the snow-capped rocky mountains but also for its streamlined "curbside to airside" design and position as one of the "greenest" airports in the world. fentress took a revolutionary approach to dia by "flipping the building upside down" to create the largest canvas roof on any structure at that time – this has since become a much imitated architectural technique.