Isengard (or Orthanc for you Pedants out there)

With post-processing. Original photo kindly taken by HW on request.

 

Historical note: A Gondorian fortification at the southern end of the Misty Mountains, at the source of the River Isen. It was granted to the Wizard Saruman by Steward Beren of Gondor, and destroyed by the Ents during the War of the Ring, though its central tower of Orthanc remained standing.

 

Notes

1 At least, it was built by Men and maintained by them for most of its history. Saruman, though, was not a Man - he was a Wizard, and hence of the 'race' of the Ainur.

2 Isengard wasn't literally made of iron, of course - the word isen, 'iron', refers to the exceedingly hard rock from which it was actually made.

 

(Source: Encyclopedia of Arda)

Done