A ceremony will take place at Cardigan Castle today, ahead of a major refurbishment of the site.
The £11m project will revamp the 900-year-old site into a facility for community and recreational use as well as for learning.
Campaigners still need to raise £150,000 to secure the project.
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A group of ex-servicemen have become the first people to climb Pen y Fan in the Brecon Beacons for 24 hours non-stop.
Thousands of athletes are in Tenby for the competition which consists of a two mile swim, a 112 mile cycle ride and a marathon.