Bill Gates is world's richest man again -

Former King of Software Sir William Gates III has regained the top spot as the world's richest man, despite spending a fortune to bump off the mosquito in Africa.

According to Forbes magazine's annual ranking of global billionaires, Gates' total net worth was estimated at $76 billion this year, up from $67 billion in 2013. This is despite giving most of his cash to charity.

His rise in wealth knocked Mexican telecoms tycoon Carlos Slim off the top spot into second place. In total, there were a record 1,645 billionaires.

To get into the top 20 you need to be worth $31 billion, up from $23 billion last year. This means we have a long way to go. Gates has been top of the list for 15 of the last 20 years.

Facebook founder Mark Zuckerberg becoming the biggest gainer in net worth. His fortune more than doubled to $28.5 billion, boosted by a sharp rise in the price of the social network's shares.

The US continues to have the most billionaires, with 492. And Europe boasted the most billionaires outside the US, with 468 in total, closely followed by Asia, which had 444 billionaires.

Landlord Gerald Grosvenor and family were the richest British family to make the list, with a net worth estimated at $13 billion. Known formally as the 6th Duke of Westminster, he owns 190 acres in Belgravia, an area adjacent to Buckingham Palace and one of London's most expensive neighbourhoods.