The Camino de Santiago is primarily marked with yellow arrows and scallop shells to provide a universal navigation system for pilgrims heading to Santiago de Compostela. The yellow arrow was popularized in the 1980s by Elias Valiña, who painted them to prevent travelers from getting lost at confusing junctions; today, they are considered the "official" and most reliable guide. The scallop shell is a medieval symbol whose lines represent the many different routes from around the world all converging at one single point. These markers are found on stone milestones, tree trunks, and tiled into city sidewalks to foster a sense of "faith and community." They ensure that millions of pilgrims can follow the ancient trails across Spain and Portugal safely, confirming that they are on the "beating heart" of the Camino even in remote rural sections.