[gphil]

Yeah, once you work through the explanation of that kind of thing the magic kind of falls out of it when you realize how the definitions fit together to produce that result.

However, I think there are certainly some areas of Math that are still pretty mysterious to the human intellect, no matter how advanced. The distribution of prime numbers and chaos come to mind.

[tel]

The Monster group is my favorite example. It may very well have the same nature of "just falling out of definitions in an unsurprising manner" but it's certainly too large for any human to ever feel that way. Monstrous Moonshine was this project and is mentioned in the article.