Structures Twenty-One and Twenty-Nine
Only the eastern end of the building, which was built c3200BC but slightly later than Structure One, is visible although geophysical survey suggests it continues around 15 metres west of the trench edge.
A faint geophysical anomaly 11 metres to the south probably represents the southern wall, suggesting the building was around the same size as Structure Twelve and had similar internal features.
After Twenty-One went out of use, its eastern wall was completely removed, possibly as a source of building stone.
All that is visible of this building is a single curved wall section jutting from the trench section to the south of Structure One.
Originally, we thought that a second wall section, protruding from the trench edge to the west of Structure Twelve, might also belong to Twenty-Nine.
In 2021, after this section was cleaned up it was clear that its construction was inferior and more akin to the later ephemeral buildings, such as Structure Twenty-Six, to the north-east, which are contemporary with the rebuild of Structure Ten.