Ada
Ada is a programming language which was developed in the early 1980s by the U.S. Department of Defense, intended to be the one standard language for all DOD programming projects. It was named after Lady Ada Lovelace, sometimes regarded as the first programmer due to her work with Charles Babbage in the 1800s. "Tech wags" enjoy noting the comparison of Lovelace's developing of programs for a machine (Babbage's Analytic Engine) which was never actually completed with the fact that it took several years after the initial promulgation of the Ada programming language before there was finally a compiler which actually implemented it fully in accordance with its standards.
Ada derives much of its syntax from Pascal, but adds concepts of modularity and object-oriented structure which were uncommon in programming languages of the time, although such things are now present in many other languages. For a time in the 1980s and 1990s, the DOD mandated that all contractors developing software for them use this language, though exceptions were often granted. This mandate was eventually lifted when Ada failed to catch on; there are many more developers now familiar with other languages than with Ada. However, Ada has a niche market in applications designed for very high reliability in areas where health or safety depend on their functioning; its extremely strong typing prevents the sort of sloppy programming errors that commonly exist in other languages.