The carriages on the Jubilee line of the London Underground seat 48 people and have standing room for as many as care to fit. If you are sitting in a largely empty carriage and 200 Americans get on, all at once, it is not going to be something you miss. They were all together, some kind of tour party on a night out, yelling, screaming, flirting, moaning, engaging in various other forms of more or less meaningful interaction and generally filling the carriage to above capacity. I *had* to look up.