Hope for Peace in South Sudan

In South Sudan, former rebel leader Riek Machar has returned to the capital Juba, to take up his position as vice-president. We will look into the political implications of this development in a country which has been affected by more than two years of conflict.

We get the latest from the US north-east Primaries as frontrunners Donald Trump and Hillary Clinton are in the lead.

The BBC's Alastair Leithead will tell us why ivory smuggling is wiping out the elephant populations in eastern and central Africa.