At Oxford.
Maybe. I think the hardest exam in the world is working a job and keeping a job, but my pup says the hardest exams in the world are the (paperless) rapid-fire interviews at big NYC banks. "What's 18X17?" "What's the square root of 289?" "What's the annualized rate of whatever?" And the damn logic puzzles she told me about, which I have now forgotten. What's the one where they pour the salt and the pepper onto the table, and ask you to quickly separate the salt from the pepper?
Oh, now I remember that one...