The world celebrates with Britain: people at home and abroad mark the birth of Kate and Prince William's baby boy. (11 PHOTOS)
The Chelsea Pensioners -- a club of retired British Army soldiers -- toast the birth of a baby boy born to Britain's Prince William and Catherine, the duchess of Cambridge. The couple's first son was born on July 22 in a central London hospital.
The British Telecom Tower displays "it's a boy" to mark the birth of a baby boy for Catherine, duchess of Cambridge, and her husband Prince William, in London on July 22.
Crowds of people try to read a notice formally announcing the birth of a son to Britain's Prince William and Catherine, the duchess of Cambridge, placed in the forecourt of Buckingham Palace in central London.
Town Crier Tony Appleton announces the birth of Prince William and Catherine's baby boy outside of the Lindo Wing of St.Mary's Hospital in London, July 22, 2013.
The Golden Jubilee Bridges (left) and the London Eye are illuminated in celebration of the birth of a baby boy for William and Catherine.
A baby announcement card and flags adorn the gift shop of Ye Olde King's Head English Pub in Santa Monica, California to celebrate the announcement of the birth of the first child to Catherine, duchess of Cambridge, and her husband Prince William.
A Mothercare store displays a poster congratulating Britain's Prince William and his wife, Catherine, on the birth of their baby boy, on Oxford Street in central London.
The crew of the Royal Navy frigate "HMS Lancaster" forms the word "BOY" on the deck to mark the birth of Britain's new prince. The ship was on patrol in the Caribbean Sea.
The Peace Tower on Parliament Hill in Ottawa is lit-up in blue to celebrate the birth of a baby boy to Britain's Prince William and Catherine. The British monarch is officially the head of state of Canada.
To celebrate the birth of British Prince William and his wife, Catherine, the CN Tower in Toronto is illuminated in blue light. The British monarch is officially the head of state of Canada.
Visitors to Niagara Falls receive notice of the sex of the royal baby indicated by the blue light illuminating the water at Niagara Falls, New York. William and Catherine, the duke and duchess of Cambridge, had a baby boy on July 22.