The following was taken from Ecclesia de Eucharistia (the bold is mine):
8. When I think of the Eucharist, and look at my life as a priest, as a Bishop and as the Successor of Peter, I naturally recall the many times and places in which I was able to celebrate it. I remember the parish church of Niegowić, where I had my first pastoral assignment, the collegiate church of Saint Florian in Krakow, Wawel Cathedral, Saint Peter's Basilica and so many basilicas and churches in Rome and throughout the world. I have been able to celebrate Holy Mass in chapels built along mountain paths, on lakeshores and seacoasts; I have celebrated it on altars built in stadiums and in city squares... This varied scenario of celebrations of the Eucharist has given me a powerful experience of its universal and, so to speak, cosmic character. Yes, cosmic! Because even when it is celebrated on the humble altar of a country church, the Eucharist is always in some way celebrated on the altar of the world. It unites heaven and earth. It embraces and permeates all creation. The Son of God became man in order to restore all creation, in one supreme act of praise, to the One who made it from nothing. He, the Eternal High Priest who by the blood of his Cross entered the eternal sanctuary, thus gives back to the Creator and Father all creation redeemed. He does so through the priestly ministry of the Church, to the glory of the Most Holy Trinity. Truly this is the mysterium fidei which is accomplished in the Eucharist: the world which came forth from the hands of God the Creator now returns to him redeemed by Christ.
During his travels, St. Pope John Paul II celebrated Mass in various, often public, locations, emphasizing the universal reach of the Eucharist. After all, the Early Christians didn't have buildings to gather in to worship. The former Pope had the mentality of the Early Christians.