According to Wikipedia, the definition of "Pilgrimage":
"Is a journey often into an unknown or foreign place, where a person goes in search of new or expanded meaning about their self, others, nature or a higher good, through the experience. It can lead to a personal transformation after which the pilgrim returns to their daily life."
Wikipedia's definition is rather encompassing, however, I have understood a "pilgrimage" to be almost exclusively religious in meaning. In Islam, there is the Hajj or annual pilgrimage to Mecca in Saudi Arabia. For Christians, there is a "pilgrimage" to the Via Dolorosa in Jerusalem, which ends with a visit to The Church of the Holy Sepulchre and for Roman Catholics, in particular, there is a "pilgrimage" to the Vatican, as well as a "pilgrimage" to the Cathedral of Santiago/(Saint James) in Northwest Spain. And of course there many other "pilgrimage" sites around the world representing different religious faiths.
But, what about non-religious "pilgrimages"....do they really exist? In our contemporary age, we use coarse sounding words, such as, "travel" or "vacation"-(in part, because Americans are only allowed, on average, about 2 weeks of "vacation" time). How often do you hear Americans-(or Westerners, in general) say, "I am on a quest" or "I am undertaking a pilgrimage to a sacred destination"....probably not too often. And rarely will you hear, " I am on a pilgrimage to a secular shrine".
Can one undertake a genuine "pilgrimage" to a non-religious shrine or significant secular site?-(i.e. a historic battlefield site, a National Cemetery, the birthplace of an Independence movement, the Laboratory of a famous Scientist, the classroom of a famous Lecturer; for example, if you are a Physics Enthusiast, a "pilgrimage" to Galileo's lecture hall at The University of Padua where he taught for 20 years....and his podium is still standing!). Would any of these examples qualify as a "pilgrimage" or as a type of secular destination designed to transform the way you view Historical Time and Reality, as well helping you become more mature about the world at large?