The G7 is the summit of the seven most industrialised countries in the world. It was established in November 1975 on the initiative of the then French president Valéry Giscard d'Estaing, although on that occasion only six major powers met: the United States, Japan, Germany, France, Great Britain and Italy. Canada was present at subsequent meetings.

French president Emmanuel Macron and British prime minister Theresa May in talks. Their two countries have always been part of the G7 ©Dan Kitwood/Getty Images

Exceptional security measures were adopted for the occasion ©Sean Gallup/Getty Images

The Sicilian town of Taormina is on lockdown ©Sean Gallup/Getty Images

US president Donald Trump will be attending the G7 summit ©Alex Wong/Getty Imaes

Taormina also saw some protests — nothing comparable in scale to the movement that clashed with authorities at the G8 in Genoa in 2001 ©Sean Gallup/Getty Images

One of the rooms hosting the G7 in Taormina, on 26 and 27 May ©Sean Gallup/Getty Images

The army was also deployed to guarantee the security of the leaders of the world's seven major industrial powers ©Sean Gallup/Getty Images

The sea is also patrolled by military vessels ©Sean Gallup/Getty Images

The G7 is the summit of the world's seven most important industrial powers ©Sean Gallup/Getty Images

The roads around Taormina are dotted with checkpoints ©Sean Gallup/Getty Images

The G7 was established in 1975 on the initiative of France ©Sean Gallup/Getty Images

Representatives of the United States, France, Great Britain, Italy, Canada, Japan and Germany are present in Taormina ©Sean Gallup/Getty Images

Vladimir Putin's Russia was excluded from the summit (which had become the G8 with its participation) as a result of the Crimea crisis ©Thomas Peter - Pool/Getty Images

The 2016 G7 was held in Japan ©Chung Sung-Jun/Getty Images

It was the then French president Valéry Giscard d'Estaing who conceived the summit ©Focke Strangmann/Getty Images

Former US president Barack Obama at the 2015 G7 in Germany ©Sean Gallup/Getty Images

From 1976 onwards the meeting became annual, and the composition of the nations present remained unchanged until 1997, when Russia joined: the G7 thus became the G8 and was also expanded to include the president of the European Commission.

In some cases the G7 has become the G8 and the G20

During these meetings, world leaders discuss the issues of greatest concern to their countries, and therefore primarily economics. The idea is to bring policymakers together on a systematic basis, so as to be able to make headway in discussions more easily. However, many have criticised G7 meetings, viewing them as insufficiently democratic bodies that in practice lead to the creation of a world "directorate". Emblematic in this regard are the popular protests organised by the alter-globalisation movement on the occasion of numerous summits, in particular the G8 held in Genoa in 2001, which was the scene of serious clashes between demonstrators and law enforcement, as well as of violence on the part of the latter.
There is also the G20, which is the G8 expanded to include emerging economies. It should be noted, finally, that the group recently reverted to the G7 format because Russia was excluded from the meetings following its armed intervention in Ukraine in 2014. A meeting of the group is being held in Taormina, Sicily, on 26 and 27 May.