The Nuclear Security Summit was a series of meetings held between world leaders in 2014 to improve measures that were in place to prevent nuclear terrorism. Nuclear terrorism would involve someone stealing nuclear weapons or materials and then using them to cause harm to people. The goal of the summit was to make sure that the governments of the world had the necessary measures in place to make sure that this did not happen. This would include things like making sure that nuclear materials were stored securely, that governments could track them, and that there were laws to punish anyone who tried to steal nuclear materials.