Nearly every teacher of the Faith has access to a church building; and a richly designed church offers more than an art history lesson or the record of a particular parish. In its deep theology, every church building is meant to be an architectural image of the Mystical Body of Christ brought to its heavenly glory, that is, Christ and his members joined with all of creation in the perfect worship of the Father. While it first may seem odd to compare a building to the union of God with his people, Scripture proves full of architectural analogies. In the Old Testament, God dwells in the Jerusalem Temple, abiding with his creation in a highly symbolic building. In the New Testament, Christ’s body becomes the new Temple, the new place where God dwells with his creation, an idea famously echoed in the Gospel of John: “he was speaking of the temple of his body” (Jn 2:21). Christians themselves now form the stones of the temple of Christ’s body, “quarried” and shaped by the Holy Spirit and assembled by Christ himself. The First Epistle of Peter minces no words in calling his Christian readers “living stones” being built up into a spiritual house (1 Pt 2:4), and Saint Paul calls the Christian community “God’s building.” Even though it may sound ordinary today, Paul’s claim is quite extraordinary: the holiest and most important building of Jewish history is now replaced by Christians themselves since they are now “God’s temple” where the Spirit dwells (1 Cor 3: 9, 16). Later, Paul calls the very same Corinthians “members” baptized into the one body of Christ (1 Cor 12:12, 17), a concept that eventually gained the name “Mystical Body.” The Mystical Body is the Church, the continuing action of Christ at work on earth through his members, hierarchically arranged to manifest the Body’s reality and its headship under Christ. Catholic church architecture and its related arts draw directly from this pre-existing spiritual reality and every church building refers to that reality in at least three ways. First, it shows the fulfillment of God’s great deeds and promises that began with the Chosen People. Second, it signifies and makes visible “the Church living in this place, the dwelling of God with men reconciled and united in Christ.”[i] Lastly, it gives a foretaste of the Christian’s heavenly future by way of a sacramental encounter with heavenly things. These concepts remain deeply profound truths of the Christian mystery, yet their artistic expressions are remarkably familiar and largely accessible for interested adults or the youngest students who delight in looking for clues. The aim of this article, then, is to provide seven interpretive lenses that can turn any tour guide into a mystagogical catechist, allowing the church building and its art to lead up to the heavenly realities they signify.