The second stronghold of Sauron. Dol Guldur was located in Mirkwood
and was the probable reason that the forests name was changed from
Greenwood the Great. The fortress was probably built between the
years of 1000 and 1100 of the Third Age. During the War of the
Ring the fortress was home to one of the Nazgûl. It was completely
destroyed by the forces of Lothlorien after the end of the War
of the Ring.
The Lord of the Rings