In today’s business landscape, silos are one of the greatest detractors from success. These detrimental, and sometimes even deadly, systems prevent innovation and collaborative thinking. In fact, throughout my nearly 30-year career as a Yale and Harvard-trained anesthesiologist, pediatrician and entrepreneur, silos have caused more harm that anything else I’ve encountered. They create lapses in communication that have catastrophic medical, interpersonal, and financial ramifications. They lead to more errors than almost anything in medicine.

However, there is a silver-lining. Despite the harmful nature of silos there are numerous people working fight them (myself included). Here are four extraordinary individuals who have overcome silos in business and challenged the siloed status quo within their respective fields, positions and organizations.

1. Frans Johansson, Founder and CEO of The Medici Group

Frans Johansson was born in a small town near Gothenburg, Sweden. He was one of the only people of color in his town, which instilled the spirit of diversity from a very young age. His teenage and college years were consumed by diverse fantasy and role-playing fiction, all of which encouraged collaboration and communication. This helped him to develop an entrepreneurial drive, and what followed was his subsequent formation of The Medici Effect, a bestselling book that’s commonly used throughout various industries to describe the innovation that happens when disciplines and ideas intersect.

The very concept of The Medici Effect is based upon breaking silos and sharing ideas, as well as adopting newer, bolder and potentially more profitable structures and systems.

Learn more about Frans Johansson.

2. Mary Miller, CEO of JANCOA

Mary Miller is a modern example of the innate human will to survive and persevere through collaborating with and assisting others. Facing severe hardship including unemployment, divorce, bankruptcy and eviction, all at the age of 30, she decided to not let her personal struggles hold her down. Eventually, Miller remarried, partnering with her husband to work on his janitorial service company. Today, that company is known as JANCOA—an award winning janitorial service company that has gone from having 65 part-time employees in the Cincinnati area to almost 600 employees cleaning almost 17 million square feet every day.

During her tenure, Miller has gone to great lengths to invest in her staff as a way to keep staff and management on the same team—and out of silos. She did so by committing herself to building a business that would attract, maintain, and inspire employees, thus combatting the 380% to 400% annual turnover that plagues the janitorial industry.

Learn more about Mary Miller.

3. Chris Schembra, CEO and Founder of 747 Club

Commonly referred to as “The Empathy Coach” Chris Schembra has done a lot of teaching about the importance of human connection and the elimination of silos that prevent people from connecting and collaborating. “Facilitating profound human connection in a deeply disconnected world,” is his mantra, and today Schembra is part-owner of the Schembra Real Estate Group, a company worth over a billion dollars and a mentor at the start-up funding and mentorship network Techstars, a producing partner at O’Henry Productions, an organization associated with 14 Tony Awards, seven Emmys, and a Grammy.

And yet, it is his work at 747 Club, a company he founded, in which he is most proud. Schembra describes their mission like this: “We help companies build, ignite, and invest in their community using our proprietary ‘16 person dinner model’ as an authority leadership platform.”

Learn more about Chris Schembra.

4. David Siegel, CEO of Investopedia

David Siegel is the CEO of Investopedia, the world’s largest financial investment education platform with over 23 million monthly unique visitors. Siegel credits the success of his company to an outlook on business that isn’t one we often hear when combing through corporate culture improvement guides. It can be summed up by a slogan that hangs from a big sign in Investopedia’s office. It says: “Be Nice. Be Aggressive.”

And it can all be tracked back to an experience that fell well out of the silo of traditional business education. Siegel’s unifying principle of management came not from an MBA or Executive Education program; it came from spending his time in Israel studying the Talmud.

The Talmud, also known as Oral Law, is a collection of commentaries on the Torah or Jewish Bible. In studying this often contradictory text, Siegel describes his time spent in the company of hundreds of different rabbis engaging in a  no-holds-barred argumentative atmosphere, where things often got heated and harsh language was not avoided. Siegel sees his study of the Talmud as the reason why Investopedia is so successful at avoiding silos.

“As CEO at Investopedia,” says Siegel, “one of the most important things that I love to foster is debate and disagreement in our environment. There are so many ways in which we take actions as a company to facilitate that debate and disagreement. Ultimately, each disagreement finds a resolution, which means that people work together toward a common goal. If rabbis over 2,000 years could do it, so can a corporation.”

Learn more about David Siegel.