Prince William touched down in the Big Apple on Monday for a two-day trip culminating in the Earthshot Prize nominations.
Upon landing in New York via commercial flight, the Prince of Wales said it was "good to be back in the United States."
It is William's second visit to the U.S. this year.
"No one does optimism and ingenuity like the American people, so it’s only right we unveil this year's Earthshot finalists in New York City," Prince William said. "Eighty years ago, the world came together in this great city to find a new way, through the U.N., to solve our shared challenges."
"I know our generation can take the bold action we need to make changes towards a healthy and sustainable world. The challenge may feel huge, but as John F Kennedy taught us, we rise to the challenge not because it is easy, but because it is hard. And vital," he added.
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After touching down at New Jersey's Newark Liberty International Airport, Prince William arrived by boat at the Billion Oyster Project on Governors Island.
The nonprofit focuses on oyster reef restoration in the New York Harbor in collaboration with communities in New York.
Kate Middleton did not join the prince for this particular trip.
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William and Kate were both on hand in Boston for the second annual Earthshot Prize awards in December.
The awards ceremony, which recognizes environmental heroes tackling climate change and sustainability efforts, had been postponed due to the death of Queen Elizabeth II in September of last year.
Prince William created the program in 2020.
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Days earlier, his younger brother was close to home as he celebrated the Invictus Games in Germany with wife Meghan Markle.
The Duke and Duchess of Sussex packed on the PDA as they celebrated Harry's 39th birthday at the athletic event.
Prince Harry founded the annual contest in 2014 as a Paralympic-style event designed to inspire military veterans around the world as they work toward overcoming battlefield injuries.