Barad-dûr

First Building

Around S.A. 1000 Sauron chose Mordor as a land to turn it into a stronghold and began to buid the Barad-dûr, because he was alerted by the growing power of the Númenóreans. Around 600 years later he secretly forged the One Ring in the fires of Mount Doom, completed the construction of Barad-dûr and strengthened its foundations with the power of the One Ring.

During the following years Sauron was able to consolidate his power and extend it into the east. However, in S.A. 3261, Ar-Pharazôn, king of Númenor, landed at the Haven of Umbar with a great host and marched north towards Mordor. Their splendour and might was so great that Sauron humbled himself before the king and came to Númenor as a hostage.

The year after the Downfall of Númenor in S.A. 3319 Sauron's spirit secretly returned to Barad-dûr. There he worked a terrible shape for himself, took up again the One Ring and prepared for war against the Eldar and the Exiles of Númenor, who had established their realms in Arnor and Gondor. He succeeded in taking Minas Ithil, but in S.A. 3430 Elendil and Gil-galad formed the Last Alliance of Elves and Men and defeated Sauron four years later in the Battle of Dagorlad. After that they passed into Mordor and began the Siege of Barad-dûr. The siege lasted for seven years, Gil-galad and Elendil were slain and in S.A. 3441 Sauron was finally defeated. Isildur son of Elendil cut the One Ring from Sauron's hand and took it for his own instead of destroying it. The Dark Tower was finally leveled but its foundations remained, because they had been strengthened with the power of the One Ring and could not be destroyed as long as that existed.

Reconstruction

Around T.A. 1050 Sauron had returned and secretly made a stronghold at Dol Guldur. Gandalf did not discover that Sauron was the master of Dol Guldur until he entered it in T.A. 2850, and in T.A. 2941 the White Council decided to attack the fortress and Sauron, who had already made plans for an attack against Dol Guldur, abandoned it. The next year Sauron secretly returned to Mordor, which the Nazgûl had prepared for him, and began to rebuild Barad-dûr in T.A. 2951. After that Sauron stayed in Barad-dûr and conducted his war on the free people of Middle-Earth from there.

On March 25, T.A. 3019 the ring-bearer Frodo Baggins succeeded in destroying the One Ring, although it was the creature Gollum who actually held the Ring as it fell into the Cracks of Doom. With the Ring destroyed Barad-dûr ultimately collapsed to ruin and Sauron was finally defeated.

A brief vision he had of swirling cloud, and in the midst of it towers and battlements, tall as hills, founded upon a mighty mountain-throne above immeasurable pits; great courts and dungeons, eyeless prisons sheer as cliffs, and gaping gates of steel and adamant: and then all passed. Towers fell and mountains slid; walls crumbled and melted, crashing down; vast spires of smoke and spouting steams went billowing up, up, until they toppled like an overwhelming wave, and its wild crest curled and came foaming down upon the land. And then at last over the miles between there came a rumble, rising to a deafening crash and roar; the earth shook, the plain heaved and cracked, and Orodruin reeled.

Vision of Samwise Gamgee from the downfall of Barad-Dûr