The UNESCO World Heritage city of Saint-Louis is perched precariously between the Atlantic Ocean and the Senegal River. And it's on borrowed time.

Satellite data show water levels plummeting at the Kakhovka Reservoir. The reservoir supplies drinking water, irrigates vast tracts of farmland, and cools Europe's largest nuclear plant.

Sweeping global trends are changing the world. As climate change heats up the planet and pushes people to migrate, far-right politicians see both a threat and an opportunity.