UNESCO uses ten selection criteria to evaluate potential World Heritage Sites.
A site must meet at least one criterion and also satisfy requirements for authenticity or integrity, along with suitable protection and management. The criteria cover cultural achievements, architectural and technological history, traditions, living cultures, landscapes, natural phenomena, geological processes, biodiversity, and habitats important for conservation.
UNESCO originally maintained separate cultural and natural criteria. In 2005, these were combined into one unified set of ten criteria. The change made the system easier to understand and allowed sites with both cultural and natural importance to be assessed within a single framework.
Meeting a criterion alone does not guarantee inscription. States first submit sites to a tentative list, then prepare nominations. Advisory bodies evaluate most nominations before the World Heritage Committee makes the final decision. This is why a famous landmark may remain outside the World Heritage List even when it appears globally significant.