Why are people risking the journey across the Mediterranean?

This week the BBC’s James Copnall has been in Calabria, southern Italy, to report on the rising number of migrants arriving by sea. The number of people arriving has more than doubled compared to this time last year. Sadly, not everyone makes it to European shores. There have been a string of disasters with hundreds of people dying in the Mediterranean this year alone. And politicians in Europe are struggling to come up with a solution. So, why are people still taking the risky journey across the waters?