The board of county commissioners of any county are hereby authorized and empowered to levy a tax, not exceeding one-half mill on the dollar, of the taxable property of the county for one year, the proceeds thereof, when collected, to be used in building and equipping a soldiers’ memorial and monument in such county in honor of the veterans of such county who served either in world war I or world war II, or both and to pay a portion of the principal and interest on bonds issued under the authority of Kan. Stat. Ann. § 12-1774, and amendments thereto, by cities located in the county. The money raised from such tax levy shall be expended, and said soldiers’ memorial and monument constructed, in the same manner as is now provided by law for the construction of public buildings.