Free learning
These are places online where one can study a subject for free. The 'qualifications' are worthless academically. The generic term is OpenCourseWare.
Coursera Wikipedia entry Very good, used it a number of times.
OpenLearn Wikipedia entry "the home of all free, open learning from The Open University".
FutureLearn Wikipedia entry a MOOC platform owned by the OU.
Udemy Wikipedia entry Seems a bit lightweight. Nothing useful relating to war or peace.
Codecademy Wikipedia entry Used it. Pretty good.
↑ the above was written in 2017. Some things have changed by 2026...
Coursera Wikipedia entry Since 2024 has ceased to be free.
OpenLearn Wikipedia entry Is still free with a wide variety of courses. You can even get 'badged' free courses.
FutureLearn Wikipedia entry is no longer free.
Udemy Wikipedia entry is no longer free.
Codecademy Wikipedia entry Still provides free courses.
EdX Wikipedia entry is no longer free.
lynda.com Wikipedia entry Taken over by LinkedIn and no longer free.
iversity Wikipedia entry Appears to still be free. However, it has just 14 courses, all political science.
...and some more (new ones?) to investigate...
IONIS - for profit MOOCs.
Udacity - for profit MOOCs.
MIT OpenCourseWare Wikipedia entry - loads of courses and material in loads of subjects.
Academic Earth Wikipedia entry - courses from a few universities in scores of subjects.
Khan Academy Wikipedia entry - aimed at schoolchildren.
Alison Wikipedia entry - lots of free short courses.
France Université Numérique Wikipedia entry - hundreds of free courses (94 in English) where you only pay for the certificate.