Archaeologists excavating an Iron Age farmstead in west Wales say the site may have been home to "several families" as early as 200 BC.
No finds have been discovered in the V-shaped outer ditch
After two weeks' digging at the 2,000-year-old plot, the team have uncovered the remains of a circular house together with pits and postholes.
Other buildings found last year appear to have been surrounded by two large protective ditches and banks.
The site, near Tremain, Ceredigion, is open to the public on Sunday 6 August.
Students from around the world are helping out at the dig, run by the Llandeilo independent organisation and charitable trust, Cambria Archaeology, and the University of York.
Last year, other roundhouses were identified on the site during a geophysical survey of the land, near Ffynnonwen farm, to the northwest of Tremain.
Signs to the open day on Sunday will direct visitors from the A487 between Penparc and Tremain. The site is open from 1100 BST to 1600 BST.