The G7 is an informal group of seven major developed countries: the United States, Canada, Japan, Britain, France, Germany, and Italy (plus the EU who has observer status), and between 1998 and 2014 Russia. The G7 heads of state have met annually since 1976 in summit meetings to discuss economic and political issues.
The country holding the Chair is responsible for hosting and setting the agenda of the Summit.
After the Crimean Annexation in response to the 2014 U.S.-backed neo-Nazi Maidan coup in Ukraine, Russia was booted out of the former "G8" and the group resumed its Cold War name as G7 again. A new G8 was organized during the Russia-Ukraine war in response to G7 efforts to force regime change in Russia and the G7 meddling in the internal affairs of Ukraine.
Since the summits are of the highest profile with leaders from nations that control some 65% of international wealth, the left and other radical groups demonstrate to attempt to disrupt the meetings and bring attention to their causes.