Hot on the heels of the G7 summit in Germany comes the Nato Summit 2022, perhaps the most scrutinised meeting of the military alliance since the Cold War, with its ambitions in eastern Europe cited by Russian President Vladimir Putin as a reason for the invasion of Ukraine.
Here, The National answers questions on the summit and looks back at its history.
When and where is the Nato Summit 2022?
The Nato Summit 2022 will take place in Madrid, Spain, from June 28 to June 30. The venue is the Recinto Ferial Ifema.
What is on the agenda?
Nato's role in guaranteeing security in Europe is facing its biggest test since the Cold War due to concerns that Mr Putin's territorial ambitions may not be limited to Ukraine.
UK Prime Minister Boris Johnson wants allies to agree to a new phase in military, political and financial support for Ukraine, and Ukrainian President Volodymyr Zelenskyy is set to make a similar case in an address.
Mr Johnson wants more defence outlay in the alliance, with the commitment to spend 2 per cent of gross domestic product being treated as a floor, rather than a ceiling.
Finland and Sweden have applied for Nato membership and the guarantee of mutual protection it brings, in response to Russia's actions.
Mr Johnson supports the Nordic countries joining but there has been resistance from Turkey, which accuses the two countries of supporting Kurdish separatist groups.
The growth of China as a military, political and economic power also concerns the western alliance.
"For the first time, we will address China and the challenges it poses to our interests, security and values," said Nato Secretary General Jens Stoltenberg, who will host the summit.
Moscow and Beijing are "openly contesting the rules-based international order", he said in the run-up to the Madrid summit.
Which countries are attending the summit?
The summit will be attended by the leaders of Nato's 30 members.
In 1949 there were 12 founding members of the alliance: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the UK and the US.
The other member countries are: Greece and Turkey (1952), Germany (1955), Spain (1982), the Czech Republic, Hungary and Poland (1999), Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia (2004), Albania and Croatia (2009), Montenegro (2017) and North Macedonia (2020).
What is the Nato Summit and how many have taken place?
Since 1949 there have been 31 Nato summits held at key moments in the alliance’s evolution.
They are used to introduce policy, invite new members, launch major initiatives and reinforce partnerships.
They are held at the North Atlantic Council's highest level possible: heads of state and government.
The summits always take place in a Nato member country and are chaired by the organisation's secretary general.