Euro 2020 has been postponed by one year until 2021 because of the coronavirus pandemic.
European football's governing body made the decision during an emergency video conference involving major stakeholders on Tuesday.
The tournament, due to take place from 12 June-12 July this summer, will now run from 11 June to 11 July next year.
The postponement provides a chance for European leagues that have been suspended to now be completed.
By moving the European Championship, Uefa now has a clash with the Women's European Championship, which is due to be held in England in 2021, beginning on 7 July.
The Nations League and the European Under-21 Championships are also scheduled to take place next summer.
Uefa said all three events will be "rescheduled accordingly", but it is currently unclear if that involves minor tweaks to dates, or large-scale postponements.
In delaying Euro 2020, Uefa said it wanted to avoid "placing any unnecessary pressure on national public services" of its 12 host countries, as well as helping allow domestic competitions to be finished.
"We are at the helm of a sport that vast numbers of people live and breathe that has been laid low by this invisible and fast-moving opponent," said Uefa president Aleksander Ceferin.
"It is at times like these, that the football community needs to show responsibility, unity, solidarity and altruism.
"The health of fans, staff and players has to be our number one priority and in that spirit, Uefa tabled a range of options so that competitions can finish this season safely and I am proud of the response of my colleagues across European football.
"There was a real spirit of co-operation, with everyone recognising that they had to sacrifice something in order to achieve the best result."
Ceferin said it was important Uefa "led the process and made the biggest sacrifice", adding it comes "at a huge cost" but "purpose over profit has been our guiding principle in taking this decision for the good of European football as a whole".
Euro play-offs moved to June
The European Championship qualifying play-offs, scheduled to begin in March, have provisionally been moved to June.
Friendly international matches due to be played this month have also been pushed back until June.
Uefa says a working group will examine calendar solutions that would allow for the completion of the current season and any other consequence of Tuesday's decisions.
Elsewhere, the South American Football Confederation (Conmebol) says this year's Copa America, due to take place from 12 June to 12 July, has been postponed until 2021.
World governing body Fifa says the newly-expanded Club World Cup, originally scheduled to take place in China in June 2021, will be postponed and a new date announced when "there is more clarity on the situation".
The organisation is also going to donate $10m (£8.3m) to the World Health Organisation (WHO) Covid-19 Solidarity Response Fund.
European Leagues committed to completing season by June 30
Many of Europe's domestic leagues - as well as the Champions League and Europa League - have been suspended following an increasing number of coronavirus cases around the continent.
Players and coaches have also been affected by the virus or been told to go into self-isolation, meaning leagues have had to shut down.
How Europe's top leagues have reacted:
- Premier League: All elite football in Britain cancelled until 4 April at the earliest subject to "conditions at the time".
- La Liga: Spain's top flight suspended until 4 April at the earliest when it will "revaluate" the situation.
- Serie A: Italy has the highest number of cases in Europe and the country is in lockdown.
- Bundesliga: Suspended until at least 2 April in Germany.
- Ligue 1: Games initially played behind closed doors in France but now suspended "until further notice".
European Leagues, which represents football leagues across the continent, says it is committed to completing European and domestic seasons by 30 June at the latest.
A mini-tournament to decide the Champions League and Europa League is expected to be one option put forward to ease fixture congestion caused by the coronavirus crisis.
Poland's representative in the meeting suggested the Champions League final could be played on 27 June and Europa League final on 24 June.
The scheduling of domestic matches in midweek alongside Champions League games or playing European games at weekends is also expected to be approved.
The qualifying rounds for the 2020-21 Champions League and Europa League tournaments may also be adjusted to take into account the delayed calendar.
What do the nations involved say?
The Norwegian FA, whose side are yet to qualify for the tournament, were first to announce the news, followed by the French and other FAs.
Mark Bullingham, chief executive of the Football Association, said English football's governing body supported the decision.
Jonathan Ford, chief executive of the Football Association of Wales, said his organisation "fully supports the decisions taken" and added that the health and safety of everyone is "the most important and only factor to consider".
French Football Federation president Noel le Graet says the governing body "fully supports" Uefa and it was a "wise and pragmatic decision".
What other limitations are there?
While the big domestic leagues have problems over television contracts to solve if games do not take place, most countries rely on the payments from Uefa that come out of major international tournaments to allow their own leagues to function properly.
These would be at risk from any movement of the European Championship and are likely to form part of any agreement.
An estimated 400 staff are working for Uefa on the Euros. It is unknown what will happen to them if the tournament does not take place for another 12 months.