After World War I, America was a place transformed. A previously isolated, rather provincial nation content to perch on the sidelines of world events, it was suddenly thrust into a position of global power. During the postwar Roaring 20s, amid an economic boom and artistic revolution, two Europeans took little-remembered trips to America. For the first time, Albert Einstein and Marie Curie crossed the pond.

I learned of the scientists’ journeys while working on my book, The Soul of Genius: Marie Curie, Albert Einstein, and the Meeting That Changed the Course of Science. Although my book focuses on their 1911 meeting at the Solvay Conference, in Brussels, I found that their trips to America had tremendous ripple effects.

When the German-born Einstein arrived on American shores, in April 1921, he was the newly crowned king of the scientific world because of his general theory of relativity. Using photographic evidence from a solar eclipse, Einstein proved that the sun could bend starlight, which helped explain the previously mysterious behavior of objects in space and time.

Marie Curie, the Polish-French queen of radioactivity, who received a Nobel Prize in 1911 for the scientific discovery that would end up killing her—we now know that large, sustained amounts of radiation do not do good things for the body—arrived in New York one month later.

Both came to America in search of support.

Noticing the rise in anti-Semitism in his native Germany after the war, Einstein solicited funds from the Jewish community to establish the Hebrew University of Jerusalem.

Curie came to collect a donation of radium—too expensive to procure herself—so she could continue developing her theory of radioactivity, which gave scientists a better understanding of atoms’ interiors. Curie’s trip was funded by Marie “Missy” Mattingly Meloney, the editor of a popular American women’s magazine called The Delineator. Meloney spent a year crowd-funding more than $100,000 to buy one gram of radium for Curie.

When Albert Einstein arrived on American shores, in April 1921, he was the newly crowned king of the scientific world.

Einstein sensed Americans’ focus on the future, which contrasted with Europe’s old-world inertia. As he put it, “Life for [Americans] is always becoming, never being.” Curie marveled at the freedom afforded by America’s wide-open spaces and the care that seemed to permeate the national conscience.

Both physicists were somewhat irritated by the atmosphere of celebrity surrounding their every appearance, their discomfort heightened by the blatant materialism that was beginning to define American culture in the Roaring 20s. But the scientists also noted that the country’s diverse population seemed full of hope and optimistic for a bright future, characteristics they believed defined American greatness.

Einstein and Curie’s discoveries were scientific breakthroughs that furthered our understanding of the universe. But relativity and radioactivity have also been used for dangerous ends—such as the atomic bombs and nuclear weapons the U.S. developed within a few decades of the physicists’ visits.

When we look back at their trips, it’s worth noting that Einstein and Curie saw America’s better angels. A century later, this is as worthy of remembrance as their scientific triumphs.

Jeffrey Orens’s The Soul of Genius: Marie Curie, Albert Einstein, and the Meeting That Changed the Course of Science is out now from Pegasus