Visible to the Naked Eyes
You can see a water mark in the pinkish area on the front of the note. When held against the light, the portraits of Dr. Clement Isong and Alhaji, Aliyu Mai-Bornu can be seen with the letters "CBN" in water mark.
There are several other easy to see security features on the N1000 note like the kinegram (The Gold Foil) on the front of the note with the coat of arms and the number "1000" which changes colour when tilted.
Similarly, the green triangle on the front of the note changes colour from green to blue when the note is tilted