I know that ALGOL language is super-uber-extremely important as a theoretical language, and it also had a variety of implementations as per Wikipedia.
However, what's unclear is, was ALGOL (pure ALGOL, not any of its derivatives like Simula) ever actually used for any "real" programming in any way?
By "real", I mean used for several good-sized projects other than programming language/CS research, or by a significant number of developers (say, > 1000).
Personally, the only ALGOL programming I have ever done was on paper, thus the curiosity.
Algol58 seems to have been the most successful in terms of important applications.
From Wikipedia:
JOVIAL is an acronym for "Jules Own Version of the International Algorithmic Language." The "International Algorithmic Language" was a name originally proposed for ALGOL 58. It was developed to compose software for the electronics of military aircraft by Jules Schwartz in 1959.
Then:
Notable systems using JOVIAL include the Milstar Communications Satellite, Advanced Cruise Missile, B-52, B-1B, B-2 bombers, C-130, C-141, and C-17 transport aircraft, F-111, F-15, F-16 (prior to Block 50), and F-117 fighter aircraft, LANTIRN, U-2 aircraft, E-3 Sentry AWACS aircraft, Navy Aegis cruisers, Army Multiple Launch Rocket System (MLRS), Army UH-60 Black Hawk helicopters, F100, F117, and F119 jet engines, the NORAD air defense & control system (Hughes HME-5118ME system) and RL-10 rocket engines. Airborne radar systems with embedded JOVIAL software include the APG-70, APG-71 and APG-73
ALGOL 68 was used in part of DRA for the same purpose. cf. Wikipedia:
The '''Defence Research Agency''' (normally known as '''DRA'''), was an executive agency of the UK Ministry of Defence (MOD) from April 1991 until April 1995. At the time the DRA was Britain's largest science and technology organisation.
DRA's Algol68 compiler was finally open-sourced in April 1999 and is now available for linux for download from sourceforge. (However an interpreter for "Algol68g" is easier to use).
ICL's Algol68 was/is S3 - It was developed by the UK company International Computers Limited (ICL) for its 2900 Series mainframes. It is a system programming language based on ALGOL 68 but with data types and operators aligned to those offered by the 2900 Series. It was the implementation language of the operating system VME.
There are (at least) two other British operating systems - Flex and Cambridge_CAP_computer - written in Algol68 variants. And also 1 Soviet OS: Эльбрус-1 (Elbrus-1), but I have yet to find any of their source code. (If anyone can find and distribute to this source code please let me know)
BTW: I believe that VME is still running - in production - as a Linux/Unixware guest VM. Mostly at Commonwealth of Nations Custom/Immigration services.
Also over the same period the USSR was using Algol68, c.f. history link. Algol68 is used in Russian telephone exchanges. And Algol58 was used in the Russian "Buran/Буран" Space Shuttle landing system.
ALGOL68 was internationalized in 1968. I suspect there are other Algol projects in other countries. esp in German, in Dutch Japanese and Chinese but I have no details.
If you want to actually tryout Algol68 and/or contribute your code, check out Rosettacode's ALGOL 68 repository, then as a class project try one of the "Tasks not implemented".