What if you want to learn more than one major? What should you do?

Some schools allow double-majors, but if you really want to get a well-rounded education, I would strongly recommend you look at colleges that provide a liberal arts education. The purpose of a liberal arts education is to help you gain widespread knowledge.

In fact, many of the ivy league schools focus on providing their students a liberal arts education because they believe it is a preparation for success in life. This is from the Harvard college website on why Harvard provides a liberal arts education (I've highlighted some key portions):

"A Harvard education is a liberal education — that is, an education conducted in a spirit of free inquiry undertaken without concern for topical relevance or vocational utility. This kind of learning is not only one of the enrichments of existence; it is one of the achievements of civilization. It heightens students' awareness of the human and natural worlds they inhabit. It makes them more reflective about their beliefs and choices, more self-conscious and critical of their presuppositions and motivations, more creative in their problem-solving, more perceptive of the world around them, and more able to inform themselves about the issues that arise in their lives, personally, professionally, and socially. College is an opportunity to learn and reflect in an environment free from most of the constraints on time and energy that operate in the rest of life.

A liberal education is also a preparation for the rest of life. The subjects that undergraduates study and, as importantly, the skills and habits of mind they acquire in the process, shape the lives they will lead after they leave the academy. Some of our students will go on to become academics; many will become physicians, lawyers, and businesspeople. All of them will be citizens, whether of the United States or another country, and as such will be helping to make decisions that may affect the lives of others. All of them will engage with forces of change — cultural, religious, political, demographic, technological, planetary. All of them will have to assess empirical claims, interpret cultural expressions, and confront ethical dilemmas in their personal and professional lives. A liberal education gives students the tools to face these challenges in an informed and thoughtful way."

More practically, a liberal arts education means that even though you choose one major, you must take classes in many different subjects -- for example, let's say you are an engineering major. That means you'll definitely take math and science classes, but in a liberal arts environment, it also means that you have to take social sciences (economics, politics) and humanities (literature, music) classes.