Police are warning of possible traffic problems in Cardiff on a weekend when the city hosts three major events.
Veterans and home front heroes are to be honoured
On Sunday, city centre roads will be shut as up to 8,000 people take part in a tribute to WWII heroes.
Highlights include a parade and a service attended by Prince Charles and the Duchess of Cornwall.
Other events this weekend include a concert by American rock band REM and a food festival - both involving road closures.
Sunday's tributes in the Wales Remembers 1939-1945 have been organised to coincide with the UK national day of commemoration, and will link up with events across the UK.
The parade, which will be led by the band of the Royal Welsh Regiment, will include veterans from the Navy, Army, RAF, Merchant Navy and Home Front workers.
There will also be a youth division with cadets, scouts, guides and schools, as well as a selection of period military vehicles.
The service at Cooper's Field will start at 1100 BST conducted by the Reverend Aled Edwards, and will include a reading by First Minister Rhodri Morgan.
Wreathes will be laid and there will be a fly-past by six RAF Hawks.
In the afternoon, Katherine Jenkins and Aled Jones will perform at a special concert, alongside harpist Catrin Finch and the Jeff Hooper Big Band.
Live footage of events from London will be shown on big screens in the city, and there will also be exhibitions and 1940s displays.
Mr Morgan said: "Wales Remembers 1939-1945 is our way of thanking all those in Wales who were involved in World War II for the sacrifices they made during those dark days.
Sunday road closures
The Hayes, Hill Street, Museum Avenue and King Edward Avenue will shut from 0630 BST
John Street will be shut from 0700 BST
Castle Street from Westgate Street to John Street during the parade
The Hayes and Hill Street will reopen at 1014 BST
"The presence of The Prince of Wales and the Duchess of Cornwall at the service shows how important this event is for the whole of Wales."
He encouraged people to attend.
"This will be a memorable occasion for the people of Wales and I urge them to make the most of it," he said.
Cardiff Council Leader Rodney Berman said it was "only right to come together to show our respect."
"Thousands of people across Wales lost their lives during WWII," he said.
"It is a fitting way to recognise the debt we owe and to show our gratitude to the men and women who made so many sacrifices during World War II to protect the freedom we all enjoy today."
The event has been organised by the Welsh Assembly Government and Cardiff Council, with the support of the Big Lottery Fund.
There will also be road closures on Saturday, with Bute Crescent in Cardiff Bay shut for a food fair, and the north end of Churchill Way will be shut between 0600 and 2100 BST for the REM concert.