From Trafalgar Square, which is an excellent place to catch people, loads of seating opportunities, and you can stand up on the top level and pick your people.
And everyone seems inclined to linger there, so brilliant place.
This guy was leafing through a tour guide, couldn't see what language it was in so no clue there, but getting ready to SEE he was. His girlfriend/wife/significantation was rummaging for something in her satchel and talking 90 to the dozen, and, as is the universal way, he was nodding as he read. And you know he wasn't massively hearing a word.
If you ever want evidence that parallel universes can exist side by side, just watch a bloke (non)listening to his other half.