Deep underneath a mountain lies a challenge like no other.

In the ultimate test of the body and mind, a new game show challenging skill, fitness and bravery starts this on S4C.

Y Siambr is set in Zip World’s popular attraction in Blaenau Ffestiniog, Bounce Below, and is designed to push competitors to their limits.

Starting Thursday, 7 March at 8pm, two teams of three friends or family go head to head, battling over a series of epic challenges across four levels of the chamber.

The aim of the game is to be the first team to reach the bottom of the chamber and to get hold of the power core.

The game show pushes competitors – and even the presenter – to their limits.

Competitors are forced to face their worst fears in the chamber, as we’ll see in the first episode when mother Ceri Hughes, team Y Plenydd from Y Ffôr, dangles 150-feet above ground on the caverns’ zip lines.

See this week’s north editions, in shops and online now