The WHO describes a functioning health system as resting on six building blocks: service delivery, health workforce, health information systems, access to essential medicines, financing, and leadership/governance -- weakness in any one block undermines the others, which is why health system strengthening projects rarely focus on a single area in isolation. The 1978 Alma-Ata Declaration, signed by WHO member states in what is now Kazakhstan, established primary health care (PHC) -- accessible, community-based, preventive-first care -- as the key strategy for achieving 'Health for All,' and its core principles were reaffirmed forty years later in the 2018 Astana Declaration. Primary health care differs from hospital-based care by being the first point of contact for most people, emphasizing prevention and continuity (such as routine checkups and immunization) over specialized treatment of advanced disease, and typically costing far less per person reached. Strong primary health care is associated with better population health outcomes at lower cost than systems built mainly around hospital care, which is one reason many African countries' health strategies explicitly prioritize PHC investment.