In reading The History of Nations, we find that, like individuals, they have their whims and their peculiarities, their seasons of excitement and recklessness, when they care not what they do. We find that whole communities suddenly fix their minds upon one object and go mad in its pursuit; that millions of people become simultaneously impressed with one delusion, and run after it, till their attention is caught by some new folly more captivating than the first.
Charles Mackay, Extraordinary Popular Delusions and the Madness of Crowds
delusion, hysteria, madness