In my first year as a qualified teacher, 1969 (really), I took my class of 7 year olds to Johannesburg Zoo on an outing.
We were having a great time until we reached the bear cage, when suddenly Eric (will never forget his name) started shrieking and flailing his arms.
The rest of us had been 'oohing' and 'aahing' at the cute cub, when I looked round in alarm and found him with his head stuck in the large protective bars in front of the cage.
Some of the other 27 children started sniffling and panicking and it took a very calm, poised and soft - spoken ME to settle them all down and send for help. Inside I was a mass of panicky blubber......
It was relatively easy to get his head out, and the day was saved, but I swear I actually felt the first million grey hairs sprout all over my scalp.