The G8 summit is an annual meeting between leaders from eight of the most powerful countries in the world.
The aim is to try to tackle global problems by discussing big issues and planning what action to take.
The leaders of the countries meet every year in a different member country.
Why's it called G8 and who's in it?
G8 stands for Group of Eight and is made up of leaders from Canada, France, Germany, Italy, Japan, Russia, the UK and the United States of America.
The leaders of these countries take it in turns to be president of the G8, with the leader of the host country acting as the president that year.
In 2013 David Cameron is president as the summit is being held in Northern Ireland, part of the UK.
How long has the G8 been happening for?
The first summit was in 1975 - but back then it was just six countries, known as the G6.
It was formed because of big worldwide money troubles in the early 1970s, which prompted the US to form something called the library group, a meeting of senior financial officials from Europe, Japan and the US.
In 1975, heads of governments became involved and they agreed to meet every year.
The G6 was made up of France, Germany, Italy, Japan, the UK and America. It then changed to G7 when Canada joined in 1976 and G8 with Russia in 1998.
What happens there?
The G8 summit is a busy schedule of meetings, statements and photographs for the press.
On the second day of the summit, leaders gather for an informal talk without lots of officials or the media. In the past leaders have discussed issues such as peace in the Middle East, aid for the developing world and how to stop terrorism.
The G8 members can agree on plans and set objectives but they can't force anyone to agree with them. However, the wealth and power of the G8 members means they are often listened to by other countries.
How long does the summit last for?
The G8 summit lasts for two days.
Why do people protest at G8 summits?
Recent summits have seen big protests and sometimes violence, meaning security is very high.
Critics say it's wrong that big countries like China and India are not represented.
There are also no African or Latin American members and some says that the G8 leaders ignore the needs of the wider world.