Here's a good example of how much global politics has changed in 2016. Back in April, leaders of the G-5 group of leading industrial nations sat down for a round-table discussion at a summit in Hannover, Germany.
A bit more than six months after, only one of the world leaders looks set to stay in politics - for now.
David Cameron resigned last June after losing a referendum where Britain chose to leave the European Union.
Barack Obama is leaving the White House in January after a shock vote last month where the Republican nominee Donald Trump was elected the next president.
Chancellor Angela Merkel is facing a key election early next year. Apart from new opponents on the left, Merkel has to deal with a growing support for anti-euro and anti-European populism parties and criticism over her refugee policy.
Francois Hollande announced last week that he would not seek a second term as French president given his low popularity among the electorate.
Matteo Renzi is handing in his resignation to the Italian president on Monday after losing a key constitutional referendum.