Gandalf described the Ring as being the "...foundation of Barad-dûr..."In 3262 Sauron was challenged by a mighty host from Númenor.
Vendar so, ker Isildur ni uničil prstana, temelji Barad-dûrja ostali celi, zato je Sauron čez 1000 let trdnjavo lahko ponovno zgradil, obstajal je kot ognjeno oko na najvišjem stolpu.