British royals Prince William and Princess Kate are visiting Boston this week, marking their first trip to the U.S. in nearly a decade.
The pair hoped to draw attention to the Earthshot Prize for environmental innovation, which they will present to a winner on Friday.
Boston was chosen as the location of the ceremony because it is the birthplace of former president John F. Kennedy, whose famous "moonshot" speech inspired Prince William to pursue a similarly ambitious goal of curbing climate change.