A landmark climate change case begins at the world court. In its largest case in history, the International Court of Justice heard testimony from officials of several small island nations on how climate change is endangering their survival.

The International Court of Justice, the United Nations’ highest judicial body, is beginning landmark hearings on global warming. Here’s a guide.

Officials from almost 100 countries are at the International Court of Justice in the Netherlands, asking the court to issue an opinion on the responsibility of certain nations to protect the planet from climate change.