Today’s History newsletter examines how one man jumpstarted Christianity, learns the latest on reversing diabetes, profiles the American who refused to be king, outlines the conclave that chooses a new pope ... and salutes the builders of these national park trails. Plus, 28 tender photos that will put a smile on your face.

IMAGE COURTESY OF NATIONAL TRUST PHOTOGRAPHIC LIBRARY/JOHN HAMMOND/BRIDGEMAN IMAGES  

He once persecuted Christians. But a roadside conversion created a voice for the new faith that found believers far from Jerusalem. How did he do it?

Related:
-- Historians unravel the mystery of Mary Magdalene
-- Conclave: How a new pope is selected

LAST DAY: Get $10 off a National Geographic subscription

PHOTOGRAPH BY UIG/BRIDGEMAN/ACI

PHOTOGRAPH BY GRETA PRATT 

Is it a map or art? These colorful designs measure a key factor for four nations, including the United States, over the next half century. What is it? 

A. Educational attainment
B. Heterogeneousness by ethnic or racial heritage
C. Per capita income by sector
D. Religious affiliation by faith

In other news:
-- America’s megachurches are rapidly expanding. That is no accident. 
-- Does religion fuel happiness?

Today’s Soundtrack: Search For Peace, McCoy Tyner

Thanks for reading today’s newsletter, edited and curated by David Beard and produced by Alisher Egamov. Catch our latest Photo of the Week—and sign up here to get our future adventures in your inbox.