A recital by Richard Burton in a film about rugby in Wales is among 500,000 clips available in a new broadcast archive.
Among them are sound recordings from 1930, TV broadcasts from the 1950s and the first Welsh-language output on S4C after the channel was launched in 1982.
The Welsh Broadcast Archive Centre will be at the National Library of Wales in Aberystwyth, Ceredigion.
It is the first archive of its type in the UK.
It has been described as "an audio-visual record of Welsh history" and the first time that the public has been granted access to over a 100 years' worth of broadcasting from BBC Wales, ITV Wales and S4C.
"It's ground-breaking," said project manager Einion Gruffudd.
"Nothing like this has happened anywhere else in the UK yet where we've got all the broadcasters from a nation coming together."
It has about 250,000 items available now, with 500,000 expected in the next year.
The archive also features Welsh heavyweight boxer Tommy Farr's 1937 fight against Joe Louis in New York - the first live broadcast from across the Atlantic.
Director Rhian Gibson said "boxes and boxes", piled high to the ceilings have been arriving for them to catalogue and sort.
The website will be available to the public from 27 March and to view or listen to the material, people will need to travel to either national library or one of the "clip corners" around Wales.
Those will initially be at Carmarthenshire Archives, West Glamorgan Archives, followed by the Wales Millennium Centre, Conwy Culture Centre, Gwynedd Archives Caernarfon, Llanrwst Library and the South Wales Miners Library.