By analysing which crises - and why these crises - produce a change in international legal discourse, this thesis aims at challenging the widespread belief that International Law is a discipline of crises. Employing a comparative analysis of three influential humanitarian crises, I will suggest that crises are not born equal as they are (mis)perceived in different ways. Crises that impact international legal discourse ought to be considered Derailed Trains: a particular branch of rare, unpredicted, and highly impactful crises.