It’s the liturgy that has always drawn me to the Catholic church. It’s the “sensible signs” that always amazed me. Every single sense is involved in the High Mass: sight (statues, crucifix, stained glass), smell (incense), sound (hymns), touch (crossing oneself, genuflection, holding the chalice), and taste (the host and the wine). The sense of sacred space is completely lacking in Protestantism.
Additionally, the communal nature is fascinating. It’s a sign that we’re all together to begin with. And as Milosz and others have pointed out, it’s self-referential and self-reinforcing.