Thousands of people will step back in time during September 2020 as hundreds of venues across Wales open their doors, including several that are not normally open to the public.
Bydd miloedd o bobl yn camu yn ôl mewn amser yn ystod mis Medi 2020 wrth i gannoedd o leoliadau ledled Cymru agor eu drysau, gan gynnwys sawl un nad ydyn nhw fel arfer ar agor i'r cyhoedd.