What is the biggest university in the world?

Can you enlighten me on the identity of the world's largest university? Is it measured by student enrollment, campus size, or some other metric? And what sets this institution apart from its peers, making it stand out as the largest in the world? I'm intrigued to learn more about its academic offerings, research capabilities, and global reach. Additionally, are there any challenges or opportunities that come with being the largest university in the world?