Prince William and Duchess Kate of Cambridge visit NY & DC

Prince William tries out one of the new technologies, a Synth-tar by Ayah Bdeir, as New York City Mayor Bill de Blasio looks on during the Innovation is GREAT Reception at Shutterstock headquarters in the Empire State Building.

Prince William visits the observation deck of the Empire State Building on Dec. 9 in New York City.

At the Creativity is GREAT Britain reception, Kate took off her Mulberry Editor coat to show her black, wrap-style dress by Seraphine, a favorite maternity brand, and her long gold necklace.

Harvey Weinstein and his wife, British fashion designer Georgina Chapman, speak to Kate at the Creativity is GREAT Britain reception to celebrate British talent in New York.

Kate speaks to Patrick Stewart and his wife, Sunny Ozell, at the Creativity is GREAT Britain lunch event to celebrate British talent in New York.

Among the performers they watched at The Door was Steven Prescod's autobiographical piece, 'Brookyn Boy.' Will was so impressed he offered to help him bring his story to the world stage, Prescod said later.

The couple watched student performances in a show put on by The Door, which serves disadvantaged youth, in New York on Dec. 9.

Will and Kate talk to students during a visit to The Door and the CityKids Foundation, which serve disadvantaged youth, in New York, on Dec. 9.

Will and Kate tour the lobby of One World Trade Center, where a mural matches her coat, after a visit to the National September 11 Memorial and Museum, Dec. 9, in New York.

Under a downpour, the couple lay flowers at the edge of one of the reflecting pools at the site, in memory of the victims of the September 11 terrorist attacks. Kate wore a fuchsia double-breasted Mulberry Editor coat.

Prince William and Duchess Kate started their final day of New York visit by laying flowers at reflecting pool at the National September 11 Museum and Memorial in downtown New York on Dec 9.

Prince William, Duke of Cambridge, right, and Catherine, Duchess of Cambridge share their popcorn with NBA Global Ambassador Dikembe Mutombo during the game between the Brooklyn Nets and the Cleveland Cavaliers at Barclays Center.

Prince William talks with Jay-Z as Kate, the Duchess of Cambridge, chats with Beyonce, during an NBA basketball game Monday night.

Big smiles all around when WIll and Kate meet Hillary and Chelsea Clinton and Chelsea's husband Marc Mezvinsky at a conservation reception in New York.

Kate chose a chic outfit to attend the reception and the NBA game in Brooklyn later, including skinny black jeans and a tweedy, sparkly blue and black jacket by Tory Burch.

Catherine, Duchess of Cambridge, accompanied by New York City's first lady, Chirlane McCray, receives flowers as she departs after a visit the Northside Center for Child Development in Harlem.

Catherine, Duchess of Cambridge, greets children as she departs from a visit the Northside Center for Child Development in Harlem with New York City's first lady, Chirlane McCray.

She got up close and personal with some the kids at the Northside Center for Child Development in Harlem.

Kate showed off her kiddie skills, sitting next to 4-year-olds April, left, and Sammy in a pre-school class at the Northside Center for Childhood Development. Some of the kids throught she was the princess from 'Frozen.'

Duchess Katehelps to wrap presents for children at Northside Center for Childhood Development,

People says goodbye to Catherine, Duchess of Cambridge, accompanied by New York City's first lady, Chirlane McCray, as they depart after a visit the Northside Center for Child Development in Harlem

12/8/14 1:18:52 PM -- New York, NY, U.S.A -- Catherine, Duchess of Cambridge, greets children as she departs from a visit the Northside Center for Child Development in Harlem with New York City's first lady, Chirlane McCray (rt). Photo by Eileen Blass, USA TODAY Staff ORG XMIT: EB 132200 ROYALS VISIT KAT 12/8/2014 [Via MerlinFTP Drop]

Meanwhile, Kate was meeting New York first lady Chirlane McCray at a Harlem child-development center, on Dec. 8.

Meanwhile, Will was wowing the pooh-bahs at the World Bank with a strong speech on the need to fight wildlife crime as a national security issue for the enite planet, in Washington on Dec. 8.

Prince William chatted with President Obama in the Oval Office on Dec. 8. Obama praised his "good work" in combating illegal trade in wildlife. Will said he was so caught up in excitement when Prince George was born, he forgot to ask if the baby was a boy or girl.

Duchess Kate

NEW YORK, NY - DECEMBER 07: Prince William, Duke of Cambridge, arrives at his hotel on December 7, 2014 in New York City. The royal couple are on an official two-day visit to New York with Prince William also due to meet President Barack Obama in Washington D.C on Monday. (Photo by Carl Court/Getty Images) ORG XMIT: 527110265 ORIG FILE ID: 460115724

NEW YORK, NY - DECEMBER 07: Prince William, Duke of Cambridge (R) and his wife, Catherine, Duchess of Cambridge, arrive at their hotel on December 7, 2014 in New York City. The royal couple are on an official two-day visit to New York with Prince William also due to meet President Barack Obama in Washington D.C on Monday. (Photo by Carl Court/Getty Images) ORG XMIT: 527110265 ORIG FILE ID: 460115720

Britain's Prince William, Duke of Cambridge, and his wife Catherine, Duchess of Cambridge, arrive at the Carlyle hotel in New York, December 7, 2014. The three-day US trip will see the Duke and Duchess of Cambridge, both 32, mix diplomacy with supporting their favorite causes and promoting British business interests. AFP PHOTO / Pool / Chad RachmanCHAD RACHMAN/AFP/Getty Images ORIG FILE ID: 535982079

NEW YORK, NY - DECEMBER 07: Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge (L) arrive at The Carlyle Hotel, where they will be staying during their official two-day visit to the United States, on December 7, 2014 in New York City. (Photo by Neilson Barnard/Getty Images) ORG XMIT: 527110265 ORIG FILE ID: 460115956

Britain's Prince William, Duke of Cambridge, and his wife Catherine, Duchess of Cambridge, are greeted by Carlyle hotel manager Giovanni Beretta as they arrive in New York, December 7, 2014. The three-day US trip will see the Duke and Duchess of Cambridge, both 32, mix diplomacy with supporting their favorite causes and promoting British business interests. AFP PHOTO / Pool / Chad RachmanCHAD RACHMAN/AFP/Getty Images ORIG FILE ID: 535982091