The current licence holders for The world at War have uploaded the entire series on their YouTube channel (available in 1080p).
A stunning series and possibly the best documentary series ever produced. First hand interviews, footage and sound effects. This would be ideal for teachers etc covering WW2 or in the run up to remembrance day (just to remind little Billy how lucky he is).
This is currently being aired on Yesterday (freeview channel 19), but you are able to watch these at your own leisure without adverts.
BONUS You don't need to pay for a TV licence to watch this as it is online. Why pay the BBC to watch a TV series made by ITV 45 years ago! ;-)