A minute's silence will be observed in Wales today on the 50th anniversary of the Aberfan disaster.
Terror Advice For Welsh Businesses
Some of Wales' biggest venues have been hearing how they can spot extremists.
Bosses from places including the Millenium Stadium, Cineworld and St David's shopping centre have been told how to prevent terror attacks.
Detective Chief Superintendent Darren Davies works in counter terrorism.
He said: "They are being briefed to be alert for anything out of the ordinary, unusual, people who appear to be taking photographs in unusual circumstances, acquiring items that may be of use for terrorist purposes.
The UK terror threat is at severe but we're being told there's no specific threat. Darren said: "There's definately no cause for alarm. It's about making people alert.
"Wales is a very safe place to live, Cardiff is a very safe place to visit. This is purely about being sensible and getting everyone aware of what they should be reporting and make them confident to do so when they feel uncomfortable."
If you have any concerns you can contact the Anti Terrorist Hotline on 0800 789 321.
Tragedy struck in the village of Aberfan 50 years ago - here's how the disaster unfolded.
Even with the coal tips removed, the landscape of Aberfan still lives in the shadow of tragedy.
50 years after the Aberfan disaster these photos remain some of the most haunting and iconic images.
Most Viewed Pictures On Heart
Recently Played Tracks
To listen live, choose your preferred location:
On TV: Spookiest Halloween Hits
7pm - 8pm
Now playing: Non-stop hit music
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...