ABC News December 8, 2014

Prince William and Duchess Kate: 9 Things That Have Happened Since They Arrived in the US

WATCH: Top 4 Highlights from Prince William and Kate Middleton's American Tour

Since touching down in New York City on Sunday night, Prince William and Duchess Kate have been making the most of every second of their trip to the States.

While the Duke made a quick side trip to Washington D.C. this afternoon to advocate for environmental issues, his pregnant wife has stayed in the Big Apple, where she's enjoyed a huge reception.

"I think we’ve had a phenomenal response to the Duchess of Cambridge in particular. I’m amazed that New Yorkers were standing out in the freezing cold weather for so long just for a 30 second glimpse of her," royals expert Robert Jobson told ABC News. "Probably not since they days of princess Diana have we seen anything like this sort of reaction."