Prince Charles has unveiled a plaque at the restored and renamed Redhouse Town Hall in Merthyr Tydfil.
He told onlookers he is "very impressed" with the building.
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Fans have been waiting for the royal couple outside Cardiff City since 6am - seven hours before they are due to arrive.
Fire crews say the Old Vicarage residents have been safely evacuated, but six have been taken to hospital for check ups.
The calm after the storm! We'll see sunny spells and blue skies at times with a few showers falling as snow over the hills.