He built a small pyramid at Saqqara, originally named "Beautiful are the places of Unas", close to the Step Pyramid of Djoser. It has been excavated by Vyse, Barsanti, Gaston Maspero, Firth, Selim Hassan, A. Husein, and Alexandre Piankoff. Its interior is decorated with a number of reliefs detailing events during his reign as well as a number of inscriptions. However, Jaromir Malek considers "the main innovation of Unas' pyramid, and one that was to be characteristic of the remaining pyramids of the Old Kingdom (including some of the queens), was the first appearance of the Pyramid Texts". These texts were inscribed in Sixth Dynasty royal versions, but Unas's texts contains verses and spells which were not included in the later 6th dynasty copies. The pyramid texts were intended to help the king in overcoming hostile forces and powers in the Underworld and thus join with the Sun God Ra, his divine father in the afterlife. The king would then spend his days in eternity sailing with Ra across the sky in a solar boat.
An example of a pyramid Text here is given below:
- Re-Atum, this Unas comes to you, A spirit indestructible...Your son comes to you, This Unas comes to you, May you cross the sky united in the dark. May you rise in lightland, the place in which you shine! (Utterance 217)