The Queen has visited the famous stones of the Giant's Causeway as part of her 90th birthday tour of Northern Ireland's scenic north coast.
The monarch and Duke of Edinburgh braved blustery conditions to view the landmark Unesco World Heritage site in Co Antrim.
The world renowned visitor site is made up of 40,000 interlocking basalt columns, the majority hexagonal, that were created in a volcanic eruption.
While that is the geological explanation, ancient folklore has it that Irish giant Finn MacCool built the causeway by hand in an effort to traverse the North Channel to do battle with a Scottish giant.
The existence of similar stone columns on the Scottish isle of Staffa helped build the legend down the centuries.
On her day of engagements on the coastline, the Queen will repeat part of a train journey she made in her coronation year.
The Royal couple will also unveil a statue to a Co Antrim soldier who won a Victoria Cross for valour in the First World War.
They landed in Northern Ireland on Monday evening for a two-day trip. Shortly after her arrival at Hillsborough Castle, the Queen met Stormont First Minister Arlene Foster and Deputy First Minister Martin McGuinness separately.
On exchanges picked up on camera, the Queen joked with Mr McGuinness that she was "still alive" and said she had been busy celebrating "two birthdays".
Afterwards, the political leaders remained tight-lipped on whether the Brexit furore was discussed in their private meetings.
The visit to the north coast marks the Queen's first round of public engagements since the UK voted to leave the European Union.
After touring the Giant's Causeway, they are visiting the nearby village of Bushmills - where they will unveil a statue to VC recipient Robert Quigg.
The soldier was awarded the highest military honour for bravery during the Battle of the Somme in 1916.
The royal couple will also attend a reception at Royal Portrush Golf Club. The seaside course is due to host the Open Championship in 2019.
In a full day of engagements, the Queen and the Duke will also take a steam train journey to the newly-opened Bellarena station on the historic Coleraine-to-Londonderry line.
The Queen travelled the same section of track in 1953, a month after her coronation.
The trip is the third high-profile royal visit to Northern Ireland in a matter of weeks, after appearances by the Prince of Wales and Duchess of Cornwall and the Duke and Duchess of Cambridge.
For the visit, the Queen wore an apple green coat and matching hat by Angela Kelly with a grey, lime and apple green silk flower print dress by Stewart Parvin - accessorised with a simple diamond brooch bar.
Neville McConachie, the visitor experience supervisor at the National Trust site, explained both theories on the causeway's creation to the Royal couple.
"She was asking about the formation of the rock and I was telling her it was either caused by nature or a giant, and I believe a giant," he said.
Mr McConachie said he told the Queen that the Scottish giant Benandonner reputedly destroyed the construct as he fled Ireland in fear of doing battle with Finn MacCool.
"People did say that he actually moved to America, but I was asking her was he may be knocking about Balmoral," he joked.
As on most days, tourists from around the world were at the causeway on Tuesday morning, with the Queen's visit providing an unexpected surprise.
They cheered and some sang God Save The Queen as the Royal cavalcade weaved its way down the coast road to the stones.
Englishman David Heaton said the Queen's appearance had been a great experience.
"It was very pleasant," he said.
"There were a lot of nice people here - a lot of foreigners here who were as excited to see the Queen as the locals were."
He added: "She's a very special woman."
The Queen also toured the visitor centre at the causeway.
She was welcomed to the centre by North Antrim MP Ian Paisley, First Minister Mrs Foster and Stormont Economy Minister Simon Hamilton.
The Royal couple met National Trust staff, rangers and volunteers who run the centre - as well as some local craftsmen - before being treated to a short animation of the famous legend of Finn McCool.
A group of local children from several different nearby schools presented the Royal visitors with gifts which included a posy of locally grown flowers, a piece of north coast basalt and a hand carved bowl made from oak by wood turner Gerard Gray of Taisie Crafts, based in north Antrim.
Grace Higgins (9), Chloe Walker (10), Kiana Walker (12) and Josh Bryant (10) said they had been nervous for their big day, but that the Royal visitors had been "really friendly", and "not at all like you see on TV".
Grace said she had been practising her curtsy for the last week, and that her ballet teachers had helped her perfect it.
Heather McLachlan, Northern Ireland director for the National Trust said: "As a conservation charity, it was a great opportunity to share our conservation work on the north coast and of course to extend our famous Northern Irish welcome."
Despite the rain, large crowds turned out to welcome the Royal couple when they later arrived at Bushmills.
After a short ceremony, the Queen unveiled the life-size bronze sculpture.
Her Majesty and the Duke of Edinburgh also spent a short time speaking with relatives of Robert Quigg - including great-nephew, retired schoolteacher Leonard Quigg.
Mr Quigg said: "She thought it was a wonderful piece. She was very impressed. She actually was able to say to me when she arrived that she had shaken the hand of Robert Quigg in 1953 when she visited Coleraine train station.
"She was very gracious. It was a tremendous occasion."
The statue, which cost almost £60,000 - most of which was fund-raised by the local community, was created by Scottish sculptor David Annad, whose other high profile commissions include a tribute to former motorcycle ace Joey Dunlop in Ballymoney, Co Antrim and Thomas "Todger" Jones VC in Runcorn, Cheshire.
The life-size figure stands rigidly to attention looking up the street towards the village war memorial where Sgt Quigg's fallen comrades were commemorated, on a plinth of seven hexagonal stones, representing each of the seven wounded soldiers he rescued from no man's land during the Battle of the Somme.
After the private lunch reception, crowds of well-wishers gathered at Coleraine station as the Queen boarded a Merlin steam train to retrace the picturesque rail journey she took a month after her coronation in 1953.
The train wound its way along the north coast with waving crowds flanking the route.
On arrival at Bellarena station, she unveiled a plaque to mark the opening of its new platforms.