Every year, thousands of migrants arrive at the northern end of the African continent. Many have traveled for years, through jungle, farmland and the vast Sahara desert, hoping to cross into Europe, where they believe a better future awaits.Last week on Up First Sunday, we told the story of Senegalese migrants embarking on the dangerous journey to Europe by sea. This week, we consider a different kind of crossing. In North Africa, Spain controls two small cities: Ceuta and Melilla. If migrants can scale the heavily fortified border fences surrounding these enclave cities, they will officially be on European soil. We check in with Ari Shapiro, the co-host of NPR's All Things Considered, as he explores the realities facing migrants just outside of the walled city of Melilla–in Nador, Morocco.This is the second episode from our series following the connections between climate change, migration and rising political extremism. Chapter 3 publishes next Sunday.