Many people dream of becoming the CEO of a major corporation, but for most it's only a far-fetched fantasy.

Though the odds of achieving this lofty goal are small, it is possible, and there are a few business professionals who have gained the opportunity to lead a Fortune 500 company. The life stories and academic credentials of this powerful segment of the world population varies widely.

Some Fortune 500 CEOs have spent their entire business careers in the U.S., while others are globetrotters who have worked in multiple countries. Many of these CEOs have graduate degrees, but some climbed to the top of the corporate ladder with only a college degree on their resume, and a few dropped out of college. For instance, the billionaire leaders of two famous Fortune 500 tech companies – Mark Zuckerberg of Facebook Inc. and Michael S. Dell of Dell Inc. – both dropped out of college to focus on their businesses.

MBA hopefuls who aspire to become a CEO someday should know that an MBA degree is not a requirement for the executive role. Among the top 100 CEOs in the Fortune 500, only about a third of these CEOs have an MBA on their resume.

Among the top 100 CEOs on the Fortune 500 list, those who did earn an MBA didn't necessarily attend a highly ranked school. Several of these CEOs earned their MBA degrees from B-schools that did not receive a rank in the U.S. News Best Business Schools rankings. For instance, Stephen Squeri, the chairman and CEO at American Express Co., earned his MBA degree from Manhattan College's O'Malley School of Business, which has an unranked full-time MBA program.

There are also some CEOs who attended MBA programs outside the U.S., including Ramon Laguarta, the chairman and CEO of PepsiCo Inc., who received his MBA from the ESADE Business School in Spain.

There are 23 B-schools whose MBA alumni are leading one of the top 100 companies on the Fortune 500 list, and a handful of these schools have more than one MBA recipient in this position. Five MBA programs have trained more than one Fortune 100 CEO, and all are highly prestigious institutions, placing among the top 10 in the U.S. News Best Business Schools rankings.

See the map below to find out which MBA programs educated one of the 100 most powerful CEOs in the U.S.

