The Seat of Seeing was an ancient stone chair on top of a watchtower and outpost on the battlemented summit of Amon Hen.
It could be reached by a long staircase.
The Seat of Seeing was established at the northern frontier of the kingdom of what would become Gondor during the Second Age by the Men of Númenór. It may have also been modified or upgraded by the time before the rule of the Stewards of Gondor and the construction of the Argonath.
At the time of the War of the Ring it too, like Amon Sûl, had long been abandoned and fallen into ruin. The last remaining feature of this once-extensive building was the Seeing Seat, an observation point situated at the top of the hill and overlooking the River Anduin, which lay far below. From here, the captain of the garrison would have had an uninterrupted view of all the terrain north, south and east of its position. It is likely that a beacon was always maintained, ready to light in case there was a need to warn Gondor of approaching attack.
- The Atlas of Middle-earth pg. 84