Lord of the Nazgūl rides through the Gate of Gondor
«In rode the Lord of the Nazgūl. A great black shape against the fires beyond he loomed up, grown to a vast menace of despair. In rode the Lord of the Nazgūl, under the archway that no enemy ever yet had passed, and all fled before his face.
All save one. There waiting, silent and still in the space before the Gate, sat Gandalf upon Shadowfax: Shadowfax who alone among the free horses of the earth endured the terror, unmoving, steadfast as a graven image in Rath Dķnen.»
(Book 5, Ch.IV, p.860.)