No existing garage accommodating or designed to accommodate more than five motor vehicles or a gasoline or other motor fuel service or filling station shall be deemed to become a nonconforming use through the subsequent erection of such school or schools, hospital, church, orphan asylum, nursing or rest home, public library, theater or opera house or other building used for theatrical or operatic purposes or for public entertainment, a municipal building or any public playground or athletic field, as defined above, within the aforesaid prescribed area.