The G7 summit has started in Cornwall, with Boris Johnson urging fellow leaders to "build back better" as the world recovers from the Covid pandemic.
The UK prime minister said it was vital to learn from the "mistakes" of the 2008 financial crisis and tackle the "scar" of inequality.
The leaders posed for the traditional "family photograph" as they gathered in the seaside resort of Carbis Bay.
The distribution of Covid vaccines is also high on the summit agenda.
US President Joe Biden is among those being hosted by Mr Johnson for the three-day meeting, as well the leaders of France, Germany, Italy, Japan and Canada.
It is the first face-to-face summit of the G7 - representing most of the world's biggest economies - since before the pandemic started early last year. European Commission President Ursula von der Leyen and European Council president Charles Michel are also attending.
In his opening remarks at the main round-table discussions, Mr Johnson said that, as the world recovered from the pandemic, it was important to "level up across our societies" and "build back better".
He added: "I actually think that we have a huge opportunity to that because, as G7, we are united in our vision for a cleaner, greener world, a solution to the problems of climate change."
The prime minister also said it was "vital that we don't repeat the mistakes of the last great crisis - the last great economic recession of 2008 - when the recovery was not uniform across all parts of society".
image copyrightPA Mediaimage captionThe Duchess of Cambridge and US First Lady Jill Biden visited a school earlier
The UK government announced it was giving £430m in aid to the Global Partnership for Education, to help the world's "most vulnerable children" get better schooling, with a "particular" focus on girls.
It was important for the world economy to rebuild in a "more equal and... in a more gender-neutral and perhaps a more feminine way" after the huge damage caused by coronavirus, Mr Johnson told his fellow leaders.
As camera crews and photographers left the meeting room at the Carbis Bay Hotel, he joked that what had been intended as a "fireside chat" had turned into a "media circus".
image copyrightGetty Imagesimage captionSeveral of the European leaders enjoyed a seaside drink before the talks started
Tweeting a photograph of himself with some of the other European leaders sitting on a seaside terrace, French President Emmanuel Macron wrote: "As always, the same union, the same determination to act, the same enthusiasm! The G7 can begin."
Mr Johnson has pledged the UK will donate more than 100 million Covid vaccines to poorer countries in the next year, while Mr Biden promised 500 million doses of Pfizer vaccines to 92 low and middle-income countries and the African Union.
The G7 nations are expected to collectively agree to provide a billion doses of Covid-19 vaccine in an effort to end the pandemic in 2022.
Before the main photograph, Mr Johnson and his wife Carrie posed one-by-one for pictures with each leader and their spouse by the sea.
image copyrightPA Mediaimage captionSecurity is tight, with thousands of extra police having been sent to Cornwall
The politicians will spend Friday in discussions before going to a reception at the nearby Eden Project, attended by the Queen, the Prince of Wales, the Duchess of Cornwall and the Duke and Duchess of Cambridge.
The summit is taking place amid huge security, following large-scale protests at previous ones.
Three people were arrested a few miles away from the venue earlier on suspicion of possession of an article with intent to commit criminal damage, and four were arrested on suspicion of conspiracy to commit public nuisance.