With landmarks across the world lit up in celebration of the birth of the Duke and Duchess of Cambridge''s first son, none were more spectacular than Niagara Falls.
The falls, which lie across the border of Ontario in Canada, and New York State in the US, were lit blue at the news of the arrival of the third-in-line to the throne.
Landmarks throughout the Commonwealth flashed both red and blue in the days leading up to birth. When the news was announced that Kate Middleton had given birth to a son, they were steady on blue.
In New Zealand, Dunedin's Larnach Castle was lit up along with nearly 40 other buildings, including the air traffic control tower of Christchurch airport, and the Sky Tower, War Memorial Museum and Cloud Event Centre in Auckland.
In London, where the baby was born, Tower Bridge heralded the news with blue lights, and the London Eye was lit a very British red, white and blue.
Fountains in Trafalgar Square will remain blue for the rest of the week.
The London Mayor, Boris Johnson, told the London Times the birth was "wonderful news".
"Huge congratulations to the Duke and Duchess on the birth of their first child who will, by virtue of being born in this great city, be a Londoner through and through," Boris Johnson said.
"I am sure millions of Londoners will be raising a glass today to toast this wonderful news."
All of Her Majesty's ships - in home or international waters - were flying the Royal Navy Ensign flag from their mast yesterday to mark the birth of the as-yet-unnamed prince.
Australia will name part of a zoo after the newborn, and Taronga Park Zoo in Sydney will receive a government donation of NZ$11,600 (A$10,000) on the young prince's behalf toward saving the bilby, an endangered rabbit-like marsupial.