Pilgrimage
To make a pilgrimage means to undertake a journey—typically in the context of religious practice—of personal or ritual significance. The journey can be external and physical (as in the case of the pilgrims journeying to Thomas Becket's tomb in Geoffrey Chaucer's The Canterbury Tales), internal and spiritual (as in the case of Christian, who narrates his own allegorical vision in The Pilgrim's Progress, by John Bunyan), or both. The tradition is ancient: Scholars have found relics and records of various forms of it that date back into preclassical times. Most major world religions have sanctioned, or still sanction, some form of sacred travel in their practices and rituals, but pilgrimage is not purely a formal religious phenomenon. Many "pilgrimages" in modern times—arguably including such secular activities as tourism, symbolic political action, and journeys of personal self-discovery—testify to the lasting power of ritual travel as a manifestation of human yearning and the search for meaning, even in an era ostensibly dominated by a culture of scientific rationalism. Pilgrimage would seem to be as revealing a human phenomenon as ever—both as ritual and as metaphor.
Ritual and place
Primative religions tended to locate the divine in particular places—the river, the sun, the volcano, the forest, and so forth. Practically speaking, if you wanted to talk to a god or goddess, you had to go for a visit. Pilgrimage, even when associated with modern monotheistic religions whose basic tenets asset that God is everywhere, harks back to that primitive religious impulse to identify particular places as sacred.