“You see a person entering the wall and appearing in a location that is in one way or another to do with the idea of walls or of Chester,” explains Petralia.

“The wall acts as a portal to other places. There’s a sequence with the Great Wall of China and showing links between that and Chester as a walled city.

“And we make links to Wales and the history of Chester as a last defence against the Welsh.”

Part of the route is accompanied by a soundtrack pumped through speakers.

For the remainder, visitors are equipped with headphones.

“There are three different journeys – a woman, a man and a man with a child,” says Petralia. “With the headphones, you can listen to their thoughts.

“I hope it’ll be exciting and visually stimulating for people.”

Up the Wall has been produced by Chester Performs, the organisation charged with driving the development of the performing arts in and around the Cheshire city.

It will also feature a giant chalk timeline of Chester’s history, a dance film installation and a mass participation game of hop-scotch.

A range of performances will also take place, including Up Summanus!, depicting the mock ritual of invoking the Gods of nocturnal thunder and wine; Into the Tilt, a harp and spoken word composition; and Red Abandon, in which artist Eva Weaver uses scarlet thread to wrap and mark objects and places of interest.

UP THE Wall takes place at Chester’s Roman Garden from 7-9pm on Friday and Saturday, free entry.

Further details at www.chesterperforms.com