Answer :
depends on the meaning of the whole context - plural pilgrims or a single pilgrim?
if it's a single pilgrim, then it'll be placed as follows -> pilgrim's place
if it's multiple pilgrims, then it'll be places as follows -> pilgrims' place
if it's a single pilgrim, then it'll be placed as follows -> pilgrim's place
if it's multiple pilgrims, then it'll be places as follows -> pilgrims' place
Pilgrims' because when there is already a s on the end of a word (e.g Thomas = Thomas' shoes) but if there was no s on the end (e.g Tom = Tom's scarf). Hope this helped!