A church is a hub for Christianity both in etymology and in a physical sense: the word can mean either the body of the Christian people, the physical building, or the worship service that happens on the sabbath. Similarly, the physical building is a hub for outreach missions, programs for youths, public service venues, with amenities for counselling, wedding officiation, and of course the rituals of the Christian faith, such as baptisms, masses or congregations, and choirs.
I'm a little surprised by the emphasis on the church as building since it does not seem essential at all to ritual (think of the early Christians who met wherever they could). I'm wondering if you could have emphasized more the repetitive practices of ritual (ex. prayer, fasting, feasting, that follow cyclical time).