World leaders are gathering in New York this week with a growing list of conflicts and crises to discuss.
The annual UN General Assembly is taking place against the backdrop of worsening war in the Middle East, and other conflicts are high on the agenda too.
A 'powder keg that risks engulfing the world'
Israeli air strikes and detonating devices have killed hundreds of people in Lebanon in the past week, threatening to ignite the all-out regional war the world has long been trying to avoid.
"Our world is in a whirlwind," UN Secretary-General Antonio Guterres said, using his opening speech to point to global challenges including wars that "rage with no clue how they will end".
"We are edging towards the unimaginable – a powder keg that risks engulfing the world," he said.
Mr Guterres, a critic of Israel's assault on Gaza, said "we should all be alarmed by the escalation" in Lebanon, where Israel says it has been targeting Hezbollah militants to prevent a terrorist attack.
"Lebanon is at the brink," he said. "The people of Lebanon, the people of Israel and the people of the world cannot afford Lebanon to become another Gaza."
US President Joe Biden told the gathered leaders a "diplomatic solution" was the "only path to lasting security" on the Israel-Lebanon border.
"Full-scale war is not in anyone's interest," he said in a speech that also pushed Israel and Hamas to agree to a long-proposed ceasefire deal.
Many other leaders spoke about the Middle East conflict, too, including the president of South Africa, whose government has brought a genocide case against Israel before the World Court.
"We South Africans know what apartheid looks like," President Cyril Ramaphosa said, referring to Israel's treatment of Palestinians. "We will not remain silent and watch as apartheid is perpetrated against others."
Turkish President Recep Tayyip Erdogan went further: "Just as Hitler was stopped by the alliance of humanity 70 years ago, Netanyahu and his murder network must be stopped by the 'alliance of humanity'," he said.
Israeli Prime Minister Benjamin Netanyahu is scheduled to speak later in the week.
Zelenskyy's 'victory plan' and Russia's 'accomplices'
Ukrainian President Volodymyr Zelenskyy has brought a "victory plan" to the US.
He's sought support for the plan from world leaders at the UN meeting before he presents it to US President Joe Biden in Washington on Thursday.
"Russia can only be forced into peace, and that is exactly what's needed," he told a special meeting of the UN Security Council, of which Russia is a permanent member.
"Putin has broken so many international norms and rules that he won't stop on his own."
He said North Korea and Russia were providing weapons to Russia, making them "de facto accomplices" to its invasion.
US Secretary of State Antony Blinken said support for Russia was "not a one-way street", and Russia was reciprocating with military commitments, technology sharing and money.
"And the more Putin gives to Pyongyang and Tehran, the more he exacerbates threats to peace and security — not just in Europe, but in the Indo-Pacific, in the Middle East, all around the globe," Mr Blinken said.
Russia's UN ambassador, Vassily Nebenzia, criticised the Security Council for hosting Mr Zelenskyy.
"Western countries could not refrain from poisoning the atmosphere once again, trying to fill the airtime with the hackneyed Ukrainian issue," he said.
Not a lot of detail is known about Mr Zelenskyy's victory plan, but he told America's ABC News it was a "bridge to a diplomatic way how to stop the war", though "not about negotiation with Russia".
Mr Biden, in his speech, said: "The good news is Putin's war has failed", because Ukraine remained free and NATO had grown in size and strength.
But he warned the world "cannot grow weary" in its support for Ukraine's defence.
Leaders put a focus on a third devastating conflict
While the wars in Ukraine and the Middle East have dominated the global conversation, more of the UN's attention is now turning to a third conflict: civil war in Sudan.
It is expected to dominate talks this week, along with those in Europe and the Middle East.
The war — the result of a power struggle between the country's two top generals and their armies — has displaced an estimated 10 million people. The UN believes more than 15,000 people have died, but some estimates put the death toll much higher.
"Gaza is not the only conflict that deserves our outrage," US President Joe Biden told the assembly, noting the war had pushed 8 million people to the brink of famine.
"The world needs to stop arming the generals, to speak with one voice and tell them, 'Stop tearing your country apart, stop blocking aid to the Sudanese people, end this war now,'" Mr Biden said.
UN Secretary-General Antonio Guterres said it was a "humanitarian catastrophe" characterised by horrific violence, including "widespread rapes and sexual assaults".
"Yet outside powers continue to interfere with no unified approach to finding peace," he said.
Biden offers some hope at an 'inflection point' in history
In what's likely to be his final address to the UN General Assembly, Joe Biden has urged world leaders to step up to deal with an "inflection point" in history.
"I truly believe we're at another inflection point in world history," the outgoing US president told the gathered leaders.
Though his speech stepped through a litany of devastating conflicts and challenges facing the world, he said: "I have hope. I know there is a way forward."
He said the world was also at an inflection point when he was first elected to office in 1972.
The international community was divided by the Cold War, conflict was about to erupt in the Middle East, and America was fighting in Vietnam.
But the world "got through that moment", he said. The nuclear threat had since eased, and the US and Vietnam have become friends, proving that "even from the horrors of war, there's a way forward".
He ended his wide-ranging 20-minute speech by reflecting on his "difficult decision" to exit the US presidential race, framing it as a lesson for other world leaders.
"There's so much more I want to get done," he said, but he'd decided it was "time for a new generation of leadership".
"My fellow leaders, never forget: some things are more important than staying in power," he said to applause.
"It's your people that matter the most."
