Who are Fifa and what do they do?

Sepp Blatter, the head of Fifa has announced he will be resigning.

It follows the recent arrests of seven of the organisation's officials on charges of corruption, which means being dishonest in a position of power.

So who are Fifa and what do they do?

Who are Fifa?

Fifa stands for (in French) Fédération Internationale de Football Association - or the International Federation of Association Football.

Fifa holds the World Cup every four years

It runs world football and is in charge of organising and promoting big football tournaments around the globe - the biggest and most famous being the World Cup.

The World Cup Final is held every four years, in a different host nation each time.

What does Fifa do?

Fifa chooses who gets to hold the World Cup by visiting the nations who have asked to host it and deciding who has presented the best plan for the tournament.

As well as organising international tournaments, Fifa sees its role as protecting and developing the game of football for everyone around the world.

Why is Fifa in the news?

Senior officials from Fifa are being investigated by officials in America, for corruption.

They're suspected of taking millions of US dollars in bribes by people who wanted football tournaments held in their country, rather than picking hosts fairly.

A separate investigation by Swiss authorities is looking into how the World Cups in Russia, in 2018 and Qatar in 2022, were awarded.

US officials quoted in an American newspaper said that Sepp Blatter, the head of Fifa, was under investigation as part of the inquiry.

Sepp Blatter resigned as Fifa's leader on Tuesday

On Tuesday Mr Blatter announced he would be stepping down as head of the organisation after 17 years in charge.

In the coming months there'll need to be another election to choose a new leader for Fifa.

Whoever gets that job will have a lot of work to do to restore trust in the organisation.