Media playback is unsupported on your device

The story behind #Neknomination

5 February 2014 Last updated at 13:17 GMT

The online drinking game 'Neknomination', which involves filming oneself whilst 'necking' a drink, has gone viral on Facebook.

Participants post their videos on social media and then nominate someone else to do the same.

Its popularity has come at a price, after a teenager died in the Republic of Ireland who allegedly took part in a 'Neknomination'.

Produced by Anne-Marie Tomchak and Neil Meads.

All our stories are at BBC.com/trending

Follow @BBCtrending on Twitter and tweet using #BBCtrending