Where people have prayed, sacrificed, meditated and refused to, from the oldest dated burials to the census returns of 2020, and where the numbers point next. Every zone on the map has a start year and an end year taken from the record, so the map shows only what the evidence can date.
Every tradition in the atlas carries 3 to 12 dated milestones of spread or contraction, each tagged with the way it moved: a founding, a trade route, a mission, a migration, a conquest, a ruler's adoption, a colonial system, a diaspora, a schism, a reform, a persecution, a revival or a turn to the secular. Counted together they show how belief has actually moved across the map. The figures below are computed live from the records.
Share of each family's dated milestones that took each route; darker to lighter as the share grows. Numbers are counts.
Share of each era's milestones that took each route. Secularization appears only in the last two rows.
Area of the zones each family occupies, weighted by strength of practice (majority 1, major 0.6, minority 0.3), in millions of square kilometers, on a log scale so small and large footprints both read. The time axis is compressed in the same way as the scrubber. After 2026 the line follows each tradition's projected change, dashed.
Each bar runs from a tradition's earliest securely dated record to its end, or to today. Faded bars ended; bars that reach the right edge are living. Hover for names, click to open on the map.
Share of the world population in each of Pew Research Center's seven groups. Two research programs count differently: the World Christian Database (grey) and Pew (in color) disagree most on China, where Pew counts most people as unaffiliated and the WCD counts many as Chinese folk religionists. Pew also changed its own method between its 2015 projection and its 2025 estimates. The gaps between lines are measurement, not change.
Total fertility rate, children per woman. 2.1 is roughly replacement level. Muslims have the youngest and fastest-growing population, the main reason Pew projects their share to rise.
Median age in years. Younger groups have more people entering childbearing years, which carries growth forward for decades.
Projected net gain or loss from people changing religion, 2010 to 2050, in millions (Pew 2015). Christianity loses the most; the unaffiliated gain the most.
Per 100 adults aged 18 to 54 raised in each group, how many have left and how many joined, pooled across 117 countries and territories covering 92% of the world (Pew 2025).
Share of each region's population, with the change since 2010 in percentage points beneath.