Nearly 300 landmarks around the world will be illuminated in green over the weekend.
It's part of the 2018 Global Greening in 48 countries to celebrate Ireland and St Patrick.
From Rome to Rio and London to Las Vegas, a host of buildings and sites around the world are turning a shade of green.
Heron Tower in London goes green | Image: Tourism Ireland
Among new sites taking part are the Luxur Obélisque at the centre of the Place de la Concorde in Paris, the Mario M Cuomo Bridge in New York, Tower 42 (the third-tallest skyscraper in London city), a giant Blue Whale skeleton in the Natural History Museum in London, the Nimb Hotel in Copenhagen, the San Mamés stadium in Bilbao, The Venetian Hotel in Las Vegas and the Lille Gate in Ypres in Belgium.
Zhongyuan Tower in China | Image: Tourism Ireland
They're joined by 'old favourites' like the Sydney Opera House, the London Eye, the Colosseum, the Leaning Tower of Pisa, the Great Wall of China and Niagara Falls.
At its inception in 2010, just the Sydney Opera House and the Sky Tower in Auckland went green.
The 'Welcome to Las Vegas' sign in Las Vegas | Image: Tourism Ireland
Niall Gibbons, CEO of Tourism Ireland, said: "St Patrick's Day traditionally marks the real start of the tourism season for us - our aim is to bring a smile to the faces of people around the world and to convey the message that Ireland offers the warmest of welcomes and great fun, as well as wonderful scenery and heritage."
