From BBC News:
Excavations at Abergwyngregyn, near Bangor, unearthed the remains of a medieval hall dating back to the 14th century, the period when Llywelyn the Great and Llywelyn the Last were fighting for Welsh independence.
Experts will be on hand on Saturday to give guided tours of the site and there will be activities for children inspired by medieval games and puzzles.
Next month, the site, which is privately owned, will be returned to pasture.
The site will be open to visitors on Saturday, 30 October, between 10am and 4pm, with children's activities from noon.