From the city below, the Watchman's Hut. Portal at bottom right.
The portal ahead (lower right, ground level) is of typically fine Inca stonework.
For a fantastic example, see this amazing one (with no mortor used), a photo from the Ollantaytambo section of my PhotoDiary.
Canon Elph - APS film (Analog)
Copyright © 1997++ Andrys Basten. Contact me if you'd like to use a photo.