St Patrick's Day - in pictures

The Sydney Opera House joins Sky Tower in Auckland, and Table Mountain in South Africa in going green to celebrate St Patrick's Day Photograph: Brendon Thorne/Getty Images

A member of the Irish Guards collapses before the arrival of the Duchess of Cambridge for the St Patrick's Day parade at the Mons barracks in Aldershot Photograph: Steve Parsons/PA

The Sky Tower in Auckland, New Zealand Photograph: Sandra Mu/Getty Images

Musicians perform as they take part in a St Patrick's Day Parade in Arbat Street in central Moscow Photograph: Misha Japaridze/AP

The Duchess of Cambridge poses for an official photograph on a visit to Aldershot barracks. The Duchess presented shamrocks to the Irish Guards during her visit Photograph: Chris Jackson/Getty Images

More than 100 parades are being held across Ireland to mark St Patrick's Day. Here, people get into the spirit in Dublin Photograph: Peter Muhly/Getty Images

A parade goer dressed as a leprechaun watches a float in Dublin Photograph: Peter Muhly/Getty Images

Colourful participants in a parade in Dublin Photograph: Niall Carson/PA

Huge crowds gather on O'Connell Street, Dublin Photograph: Niall Carson/PA

The St Patrick's Day parade moves off from Belfast city hall. The parade route took revellers to Custom House Square, where there was a free concert Photograph: Paul Faith/PA

The Monaco palace illuminated in green Photograph: Valery Hache/AFP/Getty Images

The Irish Dancing Music Association marches during the 251st annual St Patrick's Day parade in New York City Photograph: Allison Joyce/Getty Images

Members of the plumbers' union dye the Chicago river green Photograph: Brian Kersey/Getty Images

Young parade-goers Harley and Presley Eidens attend the St Patrick's Day parade on New York's 5th Avenue Photograph: Timothy A. Clary/AFP/Getty Images

Photographers take a picture of the White House and its fountain, which was dyed green Photograph: Brendan Smialowski/AFP/Getty Images

Barack Obama drinks a Guinness with his ancestral cousin Henry Healy, from Moneygall, Ireland (centre), and the owner of a pub in Moneygall, Ollie Hayes, in the Dubliner Restaurant and Pub in Washington Photograph: Carolyn Kaster/AP

The Leaning Tower of Pisa illuminated in green Photograph: Federico Scoppa/Corbis

Bagpipe players march in the St Patrick's Day parade in New York Photograph: Peter Foley/EPA

A young parade-goer watches the parade on 5th Avenue in New York Photograph: Timothy A. Clary/AFP/Getty Images

The world's largest Irish walking flag is seen during the St. Patrick's Day parade in Atlanta, Georgia Photograph: Erik S. Lesser/EPA