There are many synonyms that can be used for the phrase "the churches". Some commonly used options include "religious institutions", "places of worship", "faith communities", "spiritual centers", and "houses of God". These terms can be used interchangeably with "the churches" depending on the context and the intended meaning of the sentence. For instance, "religious institutions" might be used when referring to the organizational structure and hierarchy of different denominations, whereas "houses of God" or "spiritual centers" would be more appropriate when referring to the physical locations where people go to worship. Ultimately, the choice of synonym will depend on the writer's style and the tone of the piece they are working on.