Today, Michael Bloomberg made history, becoming the largest private donor to higher education in modern American times.

The financial-data baron and former New York City mayor, who has already given $6.4 billion to philanthropic causes, today (Nov. 18) announced in a New York Times op-ed that he has donated $1.8 billion to his alma mater, Johns Hopkins, a private research university in Baltimore, Maryland. The money will be used to support student financial aid, including loans already taken by current Hopkins students.

Americans today collectively owe an estimated $1.5 trillion in student-loan debt, a crushing financial burden for millions of college students, former students, and their families. As Quartz’s Ephrat Livni noted earlier this year, Americans who complete a bachelor’s degree can expect to owe an average of $30,500. “People who go on to graduate school can owe much more, and of course, each student’s debt burden depends on which institution they attend, their parents’ finances, and whether families can take on debt in their stead,” she writes.

Bloomberg, the son of a bookkeeper, says he was able to attend Johns Hopkins thanks to a National Defense student loan and a campus job that helped pay the bills. ”My Hopkins diploma opened up doors that otherwise would have been closed, and allowed me to live the American dream,” he wrote in the Times op-ed. “I have always been grateful for that opportunity. I gave my first donation to Hopkins the year after I graduated: $5. It was all I could afford.” He continued:

I want to be sure that the school that gave me a chance will be able to permanently open that same door of opportunity for others. And so, I am donating an additional $1.8 billion to Hopkins that will be used for financial aid for qualified low- and middle-income students. This will make admissions at Hopkins forever need-blind; finances will never again factor into decisions. The school will be able to offer more generous levels of financial aid, replacing loans for many students with scholarship grants. It will ease the burden of debt for many graduates. And it will make the campus more socioeconomically diverse.”

Of course, as Bloomberg acknowledges in his op-ed, “Hopkins is one school.” Due to the burden of tuition and the associated loans, he writes that an estimated “half of all high-achieving low- and middle-income students have not even been applying to top colleges,” denying them, and the country, an opportunity to see their potential fulfilled.

The fix Bloomberg proposes involves three basic steps: improving college advising “so that more students from more diverse backgrounds apply to select colleges;” persuading schools to increase their financial aid; and steering more alumni giving to financial aid.

“I’m increasing my personal commitment—the largest donation to a collegiate institution, I’m told,” he wrote. “But it’s my hope that others will, too, whether the check is for $5, $50, $50,000 or more.”

Bloomberg’s check eclipses the $400 million that hedge fund boss John Paulson gave to Harvard and brings Bloomberg’s total giving to Johns Hopkins to more than $3.3 billion. (That’s 23 times the size of the gift, in today’s dollars, left by Quaker entrepreneur Johns Hopkins to fund the hospital and university that would bear his name, which at the time was the largest private donor gift in US history).

Bloomberg’s message to other big donors is clear: In lieu of donating yet another fancy building with your name on it, tackle educational opportunities at the root, and liberate young Americans from the decades-long prison of student debt.

And if you must donate a piece of architecture, at least do it with a sense of humility. In 2016, Bloomberg, who grew up in Brookline, Massachusetts, donated $50 million to the Boston Museum of Science, the museum’s largest-ever private donation. He chose the Museum of Science because besides his parents, he says the museum was the most profound influence on his life (he earned his bachelors degree in electrical engineering). The money is being used to support the museum’s education center. Its new name: The William and Charlotte Bloomberg Science Education Center, named in Bloomberg’s parents’ honor.