Alabama constitution
Article IV: legislative department
Section 91

The legislature shall not tax the property, real or personal, of the state, counties, or other municipal corporations, or cemeteries; nor lots in incorporated cities and towns, or within one mile of any city or town to the extent of one acre, nor lots one mile or more distant from such cities or towns to the extent of five acres, with the buildings thereon, when same are used exclusively for religious worship, for schools, or for purposes purely charitable.