Migrants' routes encompass the primary geographical routes from tropical Africa to Europe, which individuals undertake in search of residence and employment opportunities not available in their home countries.[1][citation needed] While Europe remains the predominant destination for most migrants, alternative routes also direct migrants towards South Africa and Asia. The routes are monitored by, among others, the Spanish NGO Caminando Fronteras / Walking Borders ,[2] the European group InfoMigrants[3] and the United Nations[4]