The pyrotechnic, multicolored display lasted less than a minute against the blue afternoon sky on Dec. 2, but created an indelible reminder of the power unlocked by the first nuclear chain reaction that occurred 75 years ago at the University of Chicago.

Internationally acclaimed artist Cai Guo-Qiang’s artwork began with flashes of red, orange and blue before a thick cloud of white formed high above the roof of the Regenstein Library, adjacent to the site of the pioneering experiment that ushered in the Atomic Age at 3:25 p.m. on Dec. 2, 1942.

“Your pyrotechnic works have been described as opening a tunnel through space and time,” said Bill Brown, senior advisor to the Provost for arts at UChicago and the Karla Scherer Distinguished Service Professor in American Culture, in his introductory remarks. “Today, when the essential paradox of nuclear fission, the combined promise and threat, has never been more acute, we are honored by the imperative for reflection and aspiration that your work inspires.”

Hundreds of students, faculty and community members from across Chicago gathered to hear Cai discuss the meaning of his work before the display. “Through the complexity and paradoxes found in this artwork, I hope to express both concern and hope for developments in science and human civilization,” Cai said through an interpreter, standing in front of the Henry Moore sculpture Nuclear Energy.