Remembering Auschwitz - 70 years after liberation

Survivors of the Nazi death camp at Auschwitz in Poland have joined world leaders to mark the 70th anniversary of its liberation.

The ceremony is thought to be the last major anniversary survivors are able to attend in considerable numbers.

At least 1.1 million people - the vast majority of who were Jews - were killed there during the second world war.

This makes it the site of the largest mass murder ever recorded in human history.