Fun for families. That was the theme of the low key opening day at the Sydney Festival. A marathon winner on a treadmill set the tone in Hyde Park while a giant rubber duck sailed into Darling Harbour but not without a glitch.

For it looked as though the inflatable star of the festival was going to be a no-show. Hydraulic set open the monorail line in Cockle Bay failed.

At one point in time, we thought that maybe the duck wasn't gonna make into the harbour, into the bay, but everything was OK.

But some animal magic smiled on the crowds at Darling Harbor and the giant rubber duck sailed safely underneath.

Never seen this before. It's so cute.

Across town in Hyde Park, festival goes with theme on the ground but those who did show were caught up by Tristan Meecham's power term, running a full marathon of more than 42 kilomitres on a treadmill.

The message is - never give up, even though you'll die, you still have a good time.

Charles Bradley is getting used to be in center stage, but he walked many a hard mile around the United States to get there. Years of homelessness and hard knocks ended when he was discovered in middle age by the Daptone record company, singing in a New York club.

I believe in never give up any dreams and I believe in that God gives you something good, you just keep on going, you know, you just keep while all the times I want to give up.

The singer shares the stage in the Domain with other Daptone stars for a Super Soul Revue.

The opening night Soul concert is the first of four big free shows in the Domain this month. More will follow when the Paramedic part of the program launches in a fortnight.