The 149th Dublin Horse Show is under way with more than 120,000 people expected to event between today and Sunday.
Some of the world's top-ranked show jumpers will compete at the RDS.
Riders, horses and ponies will take part in over 160 classes and competitions.
There are also more than 350 exhibition stands.
Director General of The Irish Horse Board Alison Corbally described the event as "the pinnacle of Ireland's equestrian calendar" and an "opportunity to showcase Irish horses and riders to the world.
The show, she said, "is a significant contributor to the Irish economy each year, through qualifying events around the country and culminating this week" at the RDS.
"It is wonderful to see the homecoming of top riders, many of whom are based abroad, to compete on home soil against the best of the world," Ms Corbally added.
Speaking ahead of the event, its Director Pat Hanly said the Dublin Horse Show makes a "vital contribution to the Irish sport horse industry".
"Over the five days we will showcase the very best in horsemanship - both international and national and in keeping with the ethos of the RDS, Positive Strides which highlights the power of equine-assisted therapy and care is back at the show on Friday, Saturday and Sunday," he said.
The Nations Cup takes place in the main arena on Friday and the Defender Puissance is on Saturday.
The Rolex International Grand Prix event, with a prize of €500,000, will be held on Sunday.
