N24 aired an interesting documentary film on Tenerife accident between two 747s, considered one of the biggest pre-9⁄11 aircraft disaster. Detailed information, including released reports and reconstructed illustrations are also available from Project Tenerife website.
This accident happened long time ago (when I was few days old), the lessons learned from it proved be to useful for improvements in the regulations. Even for people outside airline industry, it shows how good communication is indeed very very important.