To answer this question, we turn to Joseph Cardinal Ratzinger (later known as Pope Benedict XVI) who answered it perfectly in his book, The Spirit of Liturgy.
Can there really be special holy places... in the world of Christian faith? Christian worship is surely a cosmic liturgy, which embraces both heaven and earth.... Is the whole world not now his sanctuary? Is sanctity not to be practiced by living one's daily life in the right way? Is our divine worship not a matter of being loving people in our daily life?... Can the sacral be anything other than imitating Christ in the simple patience of daily life?
Who ever asks questions like these touches on a crucial dimension of the Christian understanding of worship, but overlooks something essential about the permanent limits of human existence in this world, overlooks the "not yet" that is apart of Christian existence and talks as if the New Heaven and New Earth had already come. The Christ-event and growth of the Church out of all nations, the transition from Temple sacrifice to universal worship "in spirit and truth", is the first important step across the frontier, a step toward the fulfillment of the promises of the Old Testament. But is it obvious that hope has not yet fully attained its goal. The New Jerusalem needs no Temple because Almighty God and the Lamb are themselves its Temple.... But this City is not yet here.... Thus the time of the New Testament is a peculiar kind of "in-between", a mixture of "already and not yet."...
In so saying, we finally discover the answer to the question with which we started. After the tearing of the Temple curtain and the opening up of the heart of God in the pierced heart of the Crucified, do we still need sacred space, sacred time, mediating symbols? Yes, we do need them, precisely so that, through the "image", through the sign, we learn to see the openness of heaven.... We do indeed participate in the heavenly liturgy, but this participation is mediated to us through earthly signs, which the Redeemer has shown to us as the place where his reality can be found.