What is the toughest university to get into worldwide?

This is kind of out of curiosity more than anything, but I'm wondering about university admissions worldwide. I understand colleges like Harvard, Oxford, etc., have insanely competitive admissions. So, what's actually the most difficult university to get into in the world? Extra points if you know the acceptance rate!

The most selective university globally would likely be the acceptance of the Indian Institutes of Technology (IITs), particularly the IIT in Delhi and Mumbai. These institutions are renowned for their incredibly competitive entrance exams known as the Joint Entrance Exam (JEE). Each year, approximately 1.2 million students take the JEE for about 13,000 spots spread across various IITs, producing an acceptance rate of around 1%.

In Japan, the University of Tokyo is also known to have a highly competitive admissions process with an acceptance rate estimated at around 34%. However, unlike IITs, where a large number of applicants are rejected, the University of Tokyo largely relies on self-selection where only the top students apply, making it seem more selective than it may be in reality.

Finally, in the US, it's often a toss-up between Harvard, Caltech, Stanford, and MIT, all with an acceptance rate often below 5%.

It's important to remember that acceptance rates, though often used as a gauge of 'difficulty of admission', do not provide a holistic view of an institution's academic rigor or suitability for a particular student. Finally, different universities may have different requirements and expectations from their candidates, making them 'difficult' in their own ways. Always research thoroughly before making a decision!