"Otherworld journeys"

This interesting book by Carol Zaleski, professor of world religions at Smith College, examines modern reports of "near-death experiences" experienced in hospitalized patients, trauma victims, suicide survivors etc, and compares them to historical accounts of traveling outside the body (ecstatic states, travel to the underworld or heaven), as portrayed in religious epics, dramas, and myths.

This is a scholarly work with many hundreds of citations.   I'll excerpt just a brief sample:

"[In medieval times] bridges had a supernatural import.  G. A. Frank Knight attributes the mystique of bridges to a widespread primitive belief that bridge-building encroaches on the domain of the river spirit who, deprived of drowning victims, must be appeased through sacrifice.  There is evidence that ancient Roman bridge-builders placated the divinity of the Tiber by casting humans or effigies into the river.  In European folklore, as Knight points out, the tutelary river deities are Christianized into demons, every bit as hungry for human victims as were their pagan counterparts.  Hints of bridge-sacrifice are preserved in popular folktales in which the devil claims the fist soul to cross a new bridge, and also in the children's game called "London Bridge."

In Christian Europe as in ancient Rome, bridge-building was seen as a sacred as well as dangerous undertaking, and the upkeep of bridges was entrusted to clergy.  Symbolically, the supreme clerical bridge builder of Western Christendom was the pope, who became "Pontifex Maximus" in place of the Roman and Christian emperors who had inherited this title from the official charged with conserving the Pons Sublicius...

The literary history of Western eschatological bridge symbolism takes us back again to ancient Persia, to the pre-Zoroastrian tradition that souls must cross a perilous bridge in the other world..."

I had to look up the reference to the pope and bridges, which was new to me.  I studied Latin, but not being Catholic didn't appreciate the etymology of "pontiff."  Pontifex is a doublet of pontiff ("high priest") -

Often interpreted as a compound originally meaning “bridge-maker”, from Proto-Italic *pontifaks, equivalent to pōns (“bridge”) +‎ -fex (“suffix representing a maker or producer”), either metaphorically “one who negotiates between gods and men” or literally if at some point the social class which supplied the priests was more or less identical with engineers that were responsible for building bridges.

You learn something every day.