Presidents, prime ministers and chancellors are heading to Hamburg today ahead of the two-day G20 summit.
The annual conference of leaders means some of the biggest topics of the day will be argued over in detail, including climate change, security, trade and migration.
The leaders are all a mixture of mainly middle-aged men, many of whom have only been in their jobs for a few months or years, while others have been in power for more than a decade.
The variety of views and experience makes for an interesting summit.
Security is high in Hamburg with three major protests planned across the city.
Around 5,000 people are expected to be marching on Thursday evening as the first leaders arrive in Hamburg.
To help with security, 15,000 police officers will be patrolling the streets of the historic port city.
All eyes will be on the interactions between the likes of Merkel, Emmanuel Macron and Donald Trump, as well as the hotly anticipated first meeting between the US President and Russia's Vladimir Putin.
- Germany - Angela Merkel
- Argentina - Mauricio Macri
- Australia - Malcolm Turnbull
- Brazil - Michael Temer
- Canada - Justin Trudeau
- China - Xi Jingping
- France - Emmanuel Macron
- India - Narendra Modi
- Indonesia - Joko Widodo
- Italy - Paolo Gentiloni
- Japan - Shinzo Abe
- Mexico - Enrique Pena Nieto
- Russia - Vladimir Putin
- Saudi Arabia- Mohammed Al -Jadaan
- South Africa - Jacob Zuma
- South Korea - Moon Jae-in
- Turkey - Recep Erdogan
- UK - Theresa May
- US - Donald Trump
- EU - Donald tusk, Jean-Claude Juncker
Also invited are the leaders of Guinea, Netherlands, Norway, Senegal, Singapore, Spain and Vietnam.
The leaders of international organisations will also be in attendance representing the World Bank, IMF, UN, World Trade Organisation, World Heath Organisation, Economic Cooperation Organisation, Food and Agriculture Organisation, Financial Stability Board and the International Labour Organisation.