Vladimir Putin may have skipped this year's G20, but the Russian leader and his ongoing war in Ukraine still managed to loom large over the summit in Bali. 

In the early hours of Wednesday morning here on the resort island, reports of an explosion in Poland got many world leaders out of their beds. 

The source of the blast is still under investigation, but the possibility of Ukraine's war spilling beyond its borders shook many leaders. 

But by the time the Sun rose over the second and final day of the G20 summit, Russia's representative Sergei Lavrov was already on a plane back to Moscow. 

These were the big moments from the meeting in Bali. 

Leaders huddle on the sidelines to discuss blast in Poland

This was meant to be a meeting of the leaders from the world's 20 largest economies. 

But when a missile landed in Poland early this morning, members of the North Atlantic Treaty Organisation (NATO) scrambled to discuss the incident. 

Two people were killed in a village close to Ukraine's border, and Poland initially claimed the missile appeared to be Russian-made. 

The host nation Indonesia had scheduled a morning tour of a Bali mangrove park, but the event was delayed by about 90 minutes as leaders huddled to discuss the blast and its potential ramifications. 

Australia's Prime Minister Anthony Albanese was not invited along to the emergency meeting but echoed leaders' sentiments about the need for an investigation.

"We need to have a full investigation as to how this has occurred and the circumstances," he said as he met the president of the European Commission, Ursula von der Leyen.

"It must take place, and then we should consider what, as an international community, is an appropriate response."

As a member of NATO, Poland has a right to invoke a clause called Article 5 which states: "An attack against one ally is considered as an attack against all allies."

There are concerns that if Russia fired the missile — even by accident — the war in Ukraine could soon become a larger European conflict. 

But in Bali, US President Joe Biden said there was "preliminary information" that indicated it was "unlikely" the missile was fired from Russian soil. 

So if it wasn't Russia, who was it? 

No-one here at the G20 is speculating publicly just yet, but the early Wednesday morning drama was yet another example of how much war in Ukraine has dominated this summit. 

Russia bails on the G20 a day early 

First it was Russian President Mr Putin who had planned to represent his country at the G20 leaders' summit in Bali. 

Then when he cancelled last week, he sent his Foreign Minister Mr Lavrov to represent him instead. 

Now Mr Lavrov has also pulled out of the G20 summit a day early and returned home, leaving Finance Minister Anton Siluanov to represent Russia. 

It comes after a dramatic 24 hours in Bali for the Russian diplomat, who vehemently rejected reports that he had been taken to hospital for a health condition.

Despite condemnation from most other G20 leaders over Russia's war in Ukraine, Mr Lavrov held several bilateral meetings on the sidelines of the summit. 

He met with China's Foreign Minister Wang Yi, Turkey's Foreign Minister Mevlut Cavusoglu, and UN secretary-general Antonio Guterres. 

He also spoke briefly with French President Emmanuel Macron and German Chancellor Olaf Scholz. 

Then he boarded a plane at Bali's Ngurah Rai airport late Tuesday night to return home to Russia, skipping the second day of the summit altogether.

The state-run news agency Tass said Mr Lavrov's early departure was "expected."  

Mr Lavrov "completed his program at the G20 summit" and "spoke at the plenary meeting on food and energy security issues and at the session on health care", it said. 

This was also the first G20 in recent memory in which no "family photo" was scheduled. 

Usually, the summit culminates with a group shot of all attending world leaders. 

But Russian senator Alexei Pushkov claimed G20 members decided to forgo the tradition this year because they didn't want to be photographed standing near Mr Putin or his ministers. 

"Boycotts are sterile and unproductive," he wrote on his Telegram channel. 

'Most' G20 nations condemn Putin 

One of the most significant moments of every G20 summit is the leaders' declaration. 

It's a statement drafted and agreed to by every nation that lays out its priorities and concerns for the year ahead. 

This year the declaration stated that "most members strongly condemned the war in Ukraine and stressed it is causing immense human suffering and exacerbating existing fragilities in the global economy".

"The use or threat of use of nuclear weapons is inadmissible," the declaration also said.

Earlier this year, Mr Putin warned that Moscow would use "all means we have" to defend Russian territory as his war in Ukraine spiralled further from his control. 

The declaration said there were "other views and different assessments of the situation and sanctions".

It wasn't immediately clear which countries held those "other views", but it's safe to say Russia was one of them. 

Indonesia went to great lengths to hold G20 during Bali's wet season

G20 leaders may well have failed to stop the war in Ukraine. 

But Indonesia has gone to great lengths to minimise the rainfall over Bali during the summit. 

Top weather scientists, along with geophysicists and other officials, used 29 tonnes of salt in a massive cloud-seeding exercise to divert potential rain clouds from the summit venue at Nusa Dua this week. 

Indonesian Air Force planes have flown 28 sorties to seed the salt into rain clouds, to try to force them to dump rain elsewhere. 

"All clouds that grow and have the potential to enter the location of the G20 event, especially outdoor events, are rained down faster so that it doesn't rain when the event takes place at that location," Tri Handoko Seko from Indonesia's National Research and Innovation Agency said. 

But in the end, despite the huge operation, heavy rain still fell intermittently over Nusa Dua. 

But given this is Bali's wet season, it could have been a lot worse. 

The clouds parted in time for leaders to plant mangroves together at the Taman Hutan Raya Ngurah Rai forest. 

It wasn't just a team-building exercise. 

Mangroves play a key role in global conservation efforts, and the G20 leaders planted them as a symbol of the need to preserve the environment.