Charles O'Rear, 1996. Sonoma rolling-green-hill wallpaper. The most-viewed photograph in history through Windows XP.
From Wikipedia
BLISS is a system programming language developed at Carnegie Mellon University (CMU) by W. A. Wulf, D. B. Russell, and A. N. Habermann around 1970. It was perhaps the best known system language until C debuted a few years later. Since then, C became popular and common, and BLISS faded into obscurity.