Hundreds of thousands of people have flooded towns and cities around Ireland as St Patrick's Day parades and festivals took place at home and abroad.
With the centre of attention and celebrations in Dublin, some of the strange and spectacular sights marching across the city included Paddy the Dracula who celebrated 45 years in the parade, giant opera singing dolls from France, hipster leprechauns and love hearts.
Over several hours about 3,000 performers snaked their way along the 2.7km route from O'Connell Street to St Patrick's Cathedral led by Grand Marshal Brendan O'Carroll.
The creator of the irreverent hit show Mrs Brown's Boys spoke of the pride his own mother would take in him leading the thousands marching across the city.
"She'd be absolutely blown away. This would be beyond her wildest dreams - I think she thought I was going to end up in prison," the star said.
O'Carroll, joined by his wife Jennifer to lead the parade, also revealed he has written a script amid the possibility of a sequel to the film Mrs Brown's Boys D'Movie.
The comedian, writer and actor put off his latest tour in order to take up the role of Grand Marshal after being invited but missing out last year due to work commitments.
"It's been an amazing honour. It's been incredible, mind-blowing," he said.
"As a child I stood not far from the O'Connell monument in my plastic sandals, with no socks, the back out of my trousers, about seven-years-old and not knowing, not even dreaming that I'd be Grand Marshal. It's a dream come true."
The Dublin parade, which has grown into one of the largest of the world, enjoyed the second year of a three-year programme where this year's theme was Celebrate Now.
The initiative is about encouraging society to focus on the here and now rather than spending time reflecting on the past.
Dozens of elaborately decorated floats portrayed the theme and colour of a carnival while marching bands entertained one of the biggest crowds in the city for the March 17 festivities.
Musicians from Mexico took part for the first time with the San Patricio Battalion Pipe Band, formed to remember the Irish soldiers who fought with Mexicans in the war of independence against America in 1846, near the head of affairs.
President Michael D Higgins watched on from O'Connell Street with his wife Sabina who gave an excited reflection of what the parade means to her and the hundreds of thousands who lined the streets.
"I think it's just like a great happy reunion where we are all conscious of our Irishness," Mrs Higgins said.
"We open our hearts to everyone together - this is what we call inclusive and you just wish that all is well for Irish people everywhere."
The parade from Dublin was streamed online to a worldwide audience and an Irish diaspora of about 70 million.
As is becoming tradition landmarks and buildings around the world, including the Colosseum in Rome, Niagara Falls and the Sacre Coeur overlooking Paris, go green to mark the national day.
Some of the 150 sites, most instantly recognisable, charged for what has fast become a marketing coup for tourism chiefs with 65,000 euro spent on the initiative this year.
And the phenomenal exposure went deeper online with an Irish artist Eamon O'Neil selected to create a Google Doodle to mark March 17.
Taoiseach Enda Kenny sent a St Patrick's Day message while on his trip to Washington DC where he vowed that next year the hundreds of thousands of emigrants who left in the recent years of economic crisis would begin to return.
"I believe that after seven years of emigration, 2016 will be the year when the number of our people coming home will be greater than the numbers who leave," he said.
"Let me encourage fam and friends who see new job op to share them with those abroad
"The days of boom and bust are behind us together we are building a new and stronger Ireland
Mr Kenny added: "So, on this St Patrick's Day we celebrate the Irish family, 70 million strong, and our real wealth as a people, our bonds of love and kindness that reach across the generations and across the globe."
The earliest parade was held in Dingle, Co Kerry at 6am where 1,000 people recreated a tradition dating back in history to when marching bands were banned in daylight hours.
The shortest parade traditionally takes place in West Boylston, Massachusetts, where 200 people walk through a car park between two pubs in the town, Finders and Keepers.
There were also celebrations in the Caribbean island of Montserrat which shares the national holiday with Ireland.
One of the biggest parades in Northern Ireland was held in Downpatrick, Co Down, where an estimated 30,000 people crowded the streets and it was this year attended by Archbishop of Canterbury Justin Welby.
He became the first head of the Anglican church to visit the saint's burial place on St Patrick's Day for 50 years.
There were parades in Belfast, as well as in towns across Northern Ireland.
Susan Kirby, St Patrick's Festival chief executive, said the festival had taken over the country.
"I can see everybody is out wearing their green, having a great time. There's huge crowds today, it's a great day to be Irish," she said.
Organisers of the Dublin festival and parade put the number of spectators on the streets at 487,000.
Ms Kirby added: "Every year we continue to be impressed by the vision of artists seen through their parade creations and performances, and this year is no different.
"The festival parade is a true testament to the artistic talent we have here in Ireland, talent that is showcased on a global stage today as the parade is viewed by millions the world over. Many thanks to all of those who came along to enjoy the day, we were thrilled to see such a huge turnout."