Poland and Ukraine have been chosen to host the 2012 European Championships.
The BBC's Adam Easton in Warsaw and Helen Fawkes in Kiev report on Polish and Ukrainian football fans' reaction to the announcement.
Big screens carried the announcement live in Warsaw city centre.
Many fans in Poland were happy and... also surprised
There were similar reactions in other cities across the country.
Poland has never hosted an event like the Euro 2012.
And many people here believed they stood little chance against the experience of a country like Italy. Winning caught some fans by surprise.
"We assumed that Italy will win and actually it was a really big surprise for us," one fan said.
"I am very happy and very proud. So, hopefully, we will be up to the task and finish building stadiums and all the stuff that is needed for the Euro."
Poland's crumbling communist-era football grounds are well below Uefa standards. And the country lacks the hotels and highways needed for such an event.
Polish President Lech Kaczynski said the infrastructure would be built but he added there were five years of hard work ahead.
For most people though, the announcement was simply a moment to celebrate.
As one of the country's leading TV sports presenters put it, it was as if Poland had just beaten Brazil in the World Cup final.
In Ukraine, there has been a surprise reaction to the news that it has been chosen to host the Euro 2012 along with neighbouring Poland.
Poland's and Ukraine's football chiefs were delighted in Cardiff
The joint bid by the two former Soviet bloc countries had been considered as only having an outside chance of winning, while Italy had been the favourite.
Like Poland, Ukraine has never hosted a major sporting event before.
With tears in his eyes, the president of the Ukrainian Football Federation, Hryhory Surkis, said that for his country it was the greatest result in the history of the game.
Football has a passionate following here, especially since last year when Ukraine took part in the World Cup finals for the first time.
For many people, though, it was a real shock that Ukraine was chosen to co-host the Euro 2012.
"We all hoped for this, and - despite the fact that we had really very strong competitors - we hoped that the victory would be ours and, when this came true, it filled me with emotion," one fan said.
"I am really surprised and very happy that such a big event will be held in Ukraine," another fan said.
"A lot of people hoped that it would be held here, and I think it's great for our country and I feel really proud," she said.
Celebrations have been somewhat muted, as Ukraine is in the middle of a political crisis.
One TV channel said that it was a great joy for people amid the total craziness of politics.
Ukrainian President Viktor Yushchenko, who took part in the presentation of the bid in Cardiff, said it was a chance for this county to unite.
He declared this was a beautiful opportunity for Ukrainians and Poles to put on an extraordinary sporting event.