The Wise discover a stronghold of evil at Dol Guldur
Event Type: Military/Strategic
Age: 3rd Age - The Kings
'The Wise (the Istari and the chief Eldar) discover that an evil power has made a stronghold at Dol Guldur. It is thought to be one of the Nazgûl.'
RotK, Appendix B, The Tale of Years
'Some here will remember that many years ago I myself dared to pass the doors of the Necromancer in Dol Guldur, and secretly explored his ways, and found thus that our fears were true: he was none other than Sauron, our Enemy of old, at length taking shape and power again.'
Fotr, Book 2, Ch 2 The Council of Elrond