The Two Towers-Baradur and Orthanc.

[fantasticfour40]

To me, I thought the Two Towers Baradur and Orthanc looked like kind of the same and why is Baradur considered the greatest fortress in middle earth during the second and third age and for what purpose did Sauron built it?

[Morphius DOH]

If you want information about Barad-dûr go here http://www.glyphweb.com/arda/b/baraddur.html for all your answers.

[Labadal]

Barad-dur was built with the power of the One Ring, so as long as the Ring remained, Barad-dur could never be truly destroyed. I think its also larger in terms of size than Orthanc.

[Nimrandir]

Orthanc is 500 feet tal to the platform. Barad-dur is 3000 feet tall. Orthanc is only lageenough to be a small tower on it.

[Nimrandir]

These words from Tolkien say it all:

"There stood a tower of marvelous shape. It was fashioned by the builders of old, who smoothed the Ring of Isengard, and yet it seemed a thing not made by the craft of men, but riven from the bones of the earth in the ancient torment of the hills. A peak and isle of rock it was, black and gleaming hard: four mighty piers of many sided stone were welded into one, but near the summit they opened into gaping horns, their pinnacles sharp as the points of spears, keen-edged as knives. Between them was a narrow space, and there upon a floor of polished stone, written with strange signs, a man might stand five hundred feet above the plain. This was Orthanc, the citadel of Saruman, the name of which had (by design or chance) a two-fold meaning; for in the elvish speech orthanc signifies Mount Fang, but in the language of the Mark of old the cunning mind.

A strong and wonderful place was Isengard, and long it had been beautiful; and ther great lords had dwelt, the wardens of Gondor upon the West, and wise men that watched the stars. But Saruman had slowely shaped it to his shifting purposes, and made it better, as he thought, being decieved-for all those arts and subtle devices, for which he forsook his former wisdom, and which fondely he imagined were his own, came but from Mordor; so that what he made was naught, only a little copy, a childs model or a slaves fltattery, of that vast fortress, armoury, prison, furnace of great power, Barad-ur, the Dark Tower, which suffered no rival, and laughed at flattery, biding its time, secure in its pride and its inmeasurable strenght."

[MoreOrLess]

Barad-dur was built with the power of the One Ring, so as long as the Ring remained, Barad-dur could never be truly destroyed. I think its also larger in terms of size than Orthanc.

The first shot we see of Barad-dur in FOTR actually shows the latter stages of the reconstruction. Also for me when Tolkien talks of the "foundations of Barad-dur" remaining aslong as the one ring exists he's not merely talking about its physical contruction but the undercurrent of Sauron's evil that remained in middle earth.