Addressing a sea of jaunty hats and multicolored umbrellas on Sunday afternoon, Class Day speaker and Newark Mayor Cory Booker LAW ’97 reminded seniors of the vital importance of vision — of seeing others, viewing oneself as a leader, and never losing sight of the small acts that make people heroes.

Amid intermittent drizzle, a crowd of thousands — made up of soon-to-be graduates, their families and other spectators — gathered on an overcast Old Campus to celebrate the accomplishments of the Yale College class of 2013. Drawing on religious texts, oral traditions, African proverbs and personal anecdotes about his upbringing and his experiences as mayor, Booker urged seniors to remember the importance of kindness, gratitude and optimism.

“Class of 2013, I see you,” Booker said. “I see that you’re stronger than you know, more beautiful than you realize, more powerful than you imagine — but you must imagine it.”

Booker told two stories during his 45-minute speech: one about running to catch a plane at the last minute, and the second about the death of a young man who lived in his building in Newark. The first story concluded with Booker talking his way through airport security with mere seconds to spare and triumphantly securing a seat in first class on the plane, only to realize he had boarded the wrong flight.

“I was first class, but I was headed in the wrong direction,” Booker recalled in dismay.

He told the crowd that “first class in life has nothing to do with where you sit in an airplane,” explaining that he has found “first class” in his quest to improve the quality of life for citizens of Newark. Booker said he has discovered fulfillment and passion “on the corners of streets, in drug treatment centers and in the high-rise projects of Newark” rather than in material possessions or prestigious titles.

Booker stressed the importance of understanding one’s relationship to others, drawing on a metaphor of the world as a single airplane. If “we see each other, see the divinity of each other, then we will never go down — we will rise, and we will rise, and we will rise,” he said.

In his second anecdote, Booker spoke of a young man he had known before his election to city mayor who reminded him of his father. Though Booker wanted to provide mentorship to him, he became distracted by the mayoral race and was shocked to discover later that the young man had been murdered in an incident of street violence.

“How could we all crowd a funeral home for his death? Where were we for his life?” Booker asked the crowd. “I tell you, class of 2013, you’ll have days like this where you feel an incomparable sadness weighing you down. But I’ve come to realize that real courage in life is — when the chorus of chaos, when the penetrating pain descends upon you — holding onto the voice inside your head that says, ‘I must keep going. I must not quit.’”

After Booker, three student speakers took the stage to deliver individual addresses. Julia Pucci ’13 spoke about Yale metaphorically as an “absurd and wonderful” body of water, and Baobao Zhang ’13 recited her poem “March on Prospect Street,” which described her experience sledding down Science Hill. Jacob Evelyn ’13 delivered a humorous address that drew laughs from seniors in the audience.

“Yalies are not afraid to do what they love, and boy, do we love Toad’s,” Evelyn quipped.

In addition to the Class Day speeches, Director of Athletics Thomas Beckett, Master of Calhoun College Jonathan Holloway and President-elect Peter Salovey announced the winners of the Yale College student prizes.

The Snow Prize, awarded to the student who has “done the most for Yale” through intellectual achievement, character and personality, went to Julian DeFreitas ’13. A Rhodes Scholar and member of the Whiffenpoofs, DeFreitas will study the neuroscience of human attention at Oxford University next year.

The highest scholarship prizes went to John Mikitish ’13 for the humanities, Stacey Chen ’13 for the social sciences and Jonathan Liang ’13 for natural sciences or mathematics.

The Elliot and Mallory awards for sportsmanship went to Elizabeth Epstein ’13, captain of the women’s tennis team, and men’s ice hockey captain Andrew Miller ’13, who led his team to its first NCAA championship in school history this year.

Ona McConnell ’13, Bo Reynolds ’13, Max Ritvo ’13 and Ethan Rodriguez-Torrent ’13 received the David Everett Chantler Award, which honors seniors who have “exemplified qualities of courage, strength of character, and high moral purpose.”

The Nakanishi Prize for leadership in enhancing ethnic or racial relations in Yale College was awarded to Joshua Penny ’13 and Alejandro Gutierrez ’13, while Sam Martin ’13 and Ruth Montiel ’13 won the Roosevelt L. Thompson Prize for public service.

Yemurai Mangwendeza ’13 claimed the Haas Prize for social leadership, and Matthew Claudel ’13 and Bonnie Antosh ’13 took home the Louis Sudler Prize for excellence in creative and performing arts, respectively.

Senior Class Gift co-chairs Omar Nije ’13, Olivia Leitner ’13, Emily Foxhall ’13 and Katie Donley ’13 announced a $29,693 total in senior class donations raised in 2013.

Wrapping up the ceremonies on stage, the senior class video “The Legend of 2013” played on screens set up among seats in the audience. The video told the story of a fictional curse of Jeremiah Dummer, a historical Yale figure, and featured members of the class of 2013 in their respective roles on campus.

Among the administrative cameos were Yale College Dean Mary Miller ominously proclaiming “Winter is coming,” President-elect Peter Salovey debating Dean of Student Affairs Marichal Gentry on the merits of the former’s moustache, and University President Richard Levin reclining on a Myrtle, S.C., beach in a Hawaiian shirt. Daily Show host Jon Stewart and journalist Katie Couric made appearances as well.

A widespread variety of creative hats were on display during the ceremony. Students wore headgear ranging from blocks of cheese to miniature sombreros, and some sprang for the truly unique — a balloon animal and even a full unicorn head were among those spotted in the crowd. While Salovey sported a baseball cap from his high school, Dean of Undergraduate Admissions Jeffrey Brenzel sat on the stage in an appropriately-donned Harry Potter Sorting Hat.

As the celebrations came to a close, seniors waved white handkerchiefs and sang “Bright College Years” together — mirroring their rendition of it four years ago, as freshmen.

Seniors will assemble on Old Campus at 10:30 a.m. on Monday for commencement exercises.