By building the long passage at Bryn Celli Ddu, the sun can creep along it into the far reaches of the inner chamber, an atmospheric moment that many never forget.
Trwy adeiladu’r cyntedd hir ym Mryn Celli Ddu, gall yr haul ymgripio ar ei hyd i’r siambr fewnol, foment atmosfferig nad yw llawer byth yn ei anghofio.