Many mediation situations and peace processes involve crises. These crises create crucial crossroads. They can lead to a breakdown in negotiations and cause a nascent trust between the parties to crumble. But a crisis can also constitute a turning point. The parties might suddenly realize how much has already been achieved and how much would be lost if the process did not continue. Finding a way out of the crisis together can unite the parties and lead to innovative solutions. The mediators’ mandates and the way they affect their conduct can then be decisive in how mediators handle crises, which we show in this chapter. We draw from the Nordic experiences of mediation and discuss internal crises and external crises that are triggered by external factors and saboteurs – spoilers – of the peace negotiations. The chapter ends with an analysis of threats and violence against mediators, which represent a particular type of crisis in peace negotiations. The safety of mediators is an understudied issue in mediation research.