Festivals and parades across the world marked St Patrick's Day to pay tribute to Saint Patrick who brought Christianity to Ireland.

In Central Dublin, an estimated 500,000 people gathered on Saturday for the St Patrick's Day parade. Bands from Britain, the United States and Russia joined Irish volunteers in the two-hour procession through Ireland's capital city, reported the Associated Press.

Dublin City went even greener for the festival with all venues turned to green lights to create a citywide illumination for the duration of the Festival from 16 March -19 March.

Landmark buildings including the London eye, Dubai's Burj al-Arab, the leaning Tower of Pisa, the Niagara Falls in the US and the Sydney Opera House in Australia were all illuminated with green lights to commemorate the day.

In Britain, the Duchess of Cambridge, Kate Middleton, presented traditional shamrock to members of the 1st Battalion Irish Guards.

In the United States, thousands of people came to the streets to watch the St Patrick's Day parade. President Obama celebrated the day with a stop at the Dubliner Irish pub and greeted the revellers.

Take a look at the St Patrick's Day celebrations around the world:

Britain's Catherine, Duchess of Cambridge reviews a ceremony during a visit to Aldershot Barracks in Aldershot, southern England. During the visit, the Duchess presented shamrocks to the Irish Guards at a St Patrick's Day parade. REUTERS/Paul Vicente/PoolREUTERS/Paul Vicente/Pool
Duchess of Cambridge reviews a ceremony during a visit to Aldershot Barracks in Aldershot, southern EnglandREUTERS/Paul Vicente/Pool
U.S. President Barack Obama (R) celebrates St. Patrick's Day with a stop at the Dubliner Irish pubREUTERS/Jonathan Erns
Dennis O'Mann and his puppet Little Blarney of New York watch the 251st annual St. Patrick's Day Parade in New York.REUTERS/Carlo Allegri
Seven-month-old Madison Grace of New Jersey watches the 251st annual St. Patrick's Day Parade with her mother in New York.REUTERS/Carlo Allegri
The fountain on the South Lawn of the White House flows with water dyed green for St. Patrick's Day, in WashingtonREUTERS/Jonathan Ernst
Krys Freebes of New York watches the 251st annual St. Patrick's Day Parade in New York.REUTERS/Carlo Allegri
A group of children sit behind a barricade during the 251st annual St. Patrick's Day Parade in New York.REUTERS/Carlo Allegri