This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Cities such as Jerusalem, Mecca, Varanasi and Lhasa draw pilgrims by the millions for reasons that long predate any modern city planning, and the pattern of a city built up around, and sustained by, its role as a pilgrimage destination repeats across traditions that otherwise share very little. Studying that pattern as a subject in its own right, rather than as a footnote to the history of any one religion, grew into a recognized field within religious studies and anthropology in the latter half of the twentieth century.
The anthropologists Victor and Edith Turner did much of the founding work, arguing in Image and Pilgrimage in Christian Culture, published in 1978, that a pilgrimage places a person in a liminal state, stepped outside ordinary social rank and daily routine, which is part of why a pilgrimage city can function the way it does: a shared destination that levels distinctions travelers carried with them from home. Later scholarship has tested and complicated that idea considerably, but pilgrimage remains the lens through which most sacred cities are studied today.
Later researchers pushed back on how uniformly the Turners' model applied, pointing out that pilgrimage sites are also frequently sites of real economic competition, political contest and disagreement between rival groups within the same tradition, which the language of shared levelling communion tends to underplay, and most current work now treats a pilgrimage city as a site of both unity and contest at once rather than one or the other.