I was walking around the cliffs near Seal Rocks in San Francisco and you had to schutch up on a narrow path next to the cliff to get around a curve to the more or less open spot on the other side. I froze coming back. I needed to be helped and have been terrified of heights ever since. I had been there several times before with no problem. I can look over the Grand Canyon if there is a railing but no railing? Fuhget about it.