Tens of thousands of rugby fans packed Cardiff on Saturday for the Six Nations decider between Wales and Ireland.
Those who could not lay their hands on precious tickets for the Millennium Stadium filled the streets and bars nearby to lap up the atmosphere.
Many of them filled the lawns outside the City Hall, where a big screen relayed the action as Wales stormed to the holy grail of a Grand Slam.
This is the diary of a day which will remain forever in Welsh hearts.
WALES' GRAND SLAM WEBLOG
posted at 1720 GMT
Flag it up... Wales fans show their joy as the team win the grand slam
Wales have done it!
The crowd erupts as Wales complete the Grand Slam for the first time since 1978. Suddenly beer is flying through the air as if every bottle contains champagne. People hug each other and jump up and down. The tension of the second half - as Ireland put on a few points - evaporates. And now the singing starts. First it was Queen's "We are the Champions," then Tom Jones' "Delilah". There is more to come. The night is young and Wales has a Grand Slam to celebrate.
posted at 1615 GMT
After a few tense moments at the start of the match, with Ireland nudging in front, a try by Gethin Jenkins and conversion by Stephen Jones returned the party atmosphere - for those pledging their allegiance to the red dragon, at least. The men and women wearing green are beginning to look the same colour as their shirts.
posted at 1530 GMT
An Irish and a Welsh fan climb a lamppost for a better view
The game starts. The singing is over but everyone joined in while it was going on, singing both the Irish and Welsh national anthems. It's such a good natured crowd that everyone cheers after each anthem. The excitement builds as the game begins. It's virtually impossible to move around the crowd, which is static from the big screen to the front of City Hall and down across Cathays Park to the museum.
A few of the more adventurous have gained a perch. Half a dozen trees facing the big screen are bearing six, eight, sometimes 10 people. Two young men have climbed the ornate lantern opposite City Hall entrance. One wears an emerald green Irish top hat, the other is holding out a Welsh flag - partners in the party atmosphere.
posted at 1500 GMT
Two Ugandan drummers lend their rhythms to the atmosphere
Two Ugandan drummers are beating out a hectic African rhythm on half a dozen drums they have set up just yards from the Millennium Stadium. Pederson Kasume, 22, wears a red t-shirt with the slogan "0% Welsh but I live here". He and his friend, Peter Kabobha, are on a cultural exchange to south Wales, giving performances of their skills on the drums and workshops on how to play them.
Ioan Gruffudd mingles with the crowds before taking his seat
The volume of the drums seems appropriate as their rhythmns echo around Wood Street and into the Millennium Plaza, which is now a sea of mostly red as the die-hard brandish their tickets at the stadium turnstiles. One of those in the crowd is the Welsh actor Ioan Gruffudd, star of Hornblower and Titanic. On Friday he told the BBC news website he was heading back from Los Angeles especially for the game. He said: "I got into Heathrow last night and got the train down. I had some lunch with my family this morning and now we're all going to the game. I bought two debentures when the stadium opened - they've almost paid for themselves now."
Sounds of the crowd
posted at 1430 GMT
Fans mass at the stadium, waiting to go through the turnstiles
St Mary Street is a throng of rugby-loving humanity, slowly bleeding from green to red as more home supporters pour into the city. What should be the country's busiest road is jammed with fans, dozens of them with airhorns. It is becoming the battle of the airhorns as rival groups compete with toots and pneumatic riffs. It's just as well cars are not allowed in the streets as none would have a chance of getting though. Nearer the stadium, the crowd is even more compact as it is chanelled down Wood Street to the gates.
posted at 1400 GMT
Three people are picked out from the crowd by the camera at the big screen to take part in a lucky dip to win two tickets to the game - an Irishman wearing a green top called John, 24-year-old Kate Freeman and 49-year-old Nigel Evans, both from Pembrokeshire. Kate was on the shoulders of a friend when the camera focused on her and she could not believe her luck at being picked.
A group of Welsh fans getting into the spirit
Each had a choice of a green, white or red envelope. The Irishman chose the green envelope, Kate chose the white one and Nigel chose the red one. The Irishman opened his first - it was a £20 drinks voucher. All eyes were on Kate. Her hands trembled as she opened hers and it was... a £20 drinks voucher. Nigel opened his and there inside were two tickets for today's game. The estate agent was here on his own and now has the job of finding someone else to take to the match with him.
He said: "I can't believe it, out of all those people. I've been here since 11.15 and was one of the first at the barriers, just waiting for it all to happen. I chose the red envelope because it was Wales. It's got to be too corny. I will wait and see what happens now. If I see someone I know from Pembrokeshire, I will give them a spare ticket."
posted at 1345 GMT
City Hall is packed as thousands of people watch the climax of the Italy-France first-half. Long queues have formed for the food and drink on sale as well as the ladies' toilets inside City Hall. The big screen is the focus of everyone's attention but really it's only an entertainment while they wait for the big game, now less than two hours away.
posted at 1330 GMT
Charlotte's fans' merchanise was selling like hot cakes
The road closures kick in and the carnival atmosphere's really starting. Four mounted police officers are walking past the Hilton hotel. They're looking relaxed and, hopefully, it will be a quiet day out for them. Flag seller Charlotte, 35, has been selling rugby memorabilia in Queen Street for almost 20 years. She says it's the best atmosphere there's ever been at a rugby game in the city. "It's mad here, " she said. "It's an absolutely amazing atmosphere. Everyone here's so happy." She's one of the many thousands without tickets but says she'll watch the game in a bar nearby.
Among those making their way across the car-free roads to the big screen at City Hall is a group of 20 from Mumbles in Swansea. John Jones, 40, is a member of Mumbles rugby club. He and friends travelled from Wales' second city to the capital in a double-decker party bus. Balancing a case of lager on his shoulder, he said: "I have not got a ticket, I've just come up for the atmosphere. It's like a carnival. The group were part of an increasing throng of people making their way to City Hall.
posted at 1315 GMT
Not to be outdone, these Irish lads dressed as leprechauns
In The Friary, the terraces outside bars are packed wth Irish and Welsh fans mingling, laughing and joking with each other. Queen Street now seems to be very thin on shoppers, but there are plenty of street sellers, people standing round in strange costumes or draped in Welsh or Irish flags. Two female Welsh fans are wearing spangly cowboy hats with red dragons on the front, and occasionally someone lets off an airhorn.
Not to be left out, Irish fans had brought their over-sized green shamrock hats and even leprechaun costumes to wear in support of their team. Everyone is enjoying themselves and all the streets around are packed and the crowds are thronging.
posted at 1245 GMT
Tom and Iwan Last make their way to the match, carrying a Welsh flag
Tom Last, 38, from Llandegfan on Anglesey, and his eight-year-old son Iwan - a player for Bangor under-10s rugby team - both have tickets to the game. Mr Last said: "I put my name down on the list at the club in January. I wanted to get six for the whole family but was lucky to just get two." He said they drove down from north Wales on Thursday and have been staying at a hotel in Hereford since. "It was as close as we could get a hotel," he added. "We drove down this morning after Iwan decided that a 5.15 start was late enough." Mr Last said : "I think it's going to be a tight game but I think that Wales will win something like 23-19."
Also going inside the Millennium Stadium are Alan Woodley, 30, from Neath, and his girlfriend Leane Jackson. The couple were able to get tickets because her uncle holds debentures. She said: "It's an amazing atmosphere. After the England game there was a pretty good chance of a Grand Slam."
posted at 1200 GMT
The stadium is hosting a capacity crowd for Wales' grand slam decider
The last of the Saturday morning shoppers are preparing to leave as the city's pavements throng with joyous rugby fans bedecked in either red or green. This is biggest rugby game for Wales in 27 years - and it shows.