To better understand the world, one can say "to broaden one's horizons" or "to expand one's knowledge." These expressions come from the idea of expanding one's perspective, or increasing one's understanding of the world beyond their current pmited view. Here are a few examples:

"Travepng to new countries is a great way to broaden your horizons."
"Reading books and watching documentaries can help you expand your knowledge of the world."
"Meeting people from different cultures can be an eye-opening experience and broaden your perspective."

In these examples, "broaden your horizons" means to increase one's knowledge and understanding of the world, and "expand your knowledge" means to learn more about various subjects.