The programmes

Grid reference: ST 532 942

Filmed 10-15 August 2003, first screened 20 June 2004

For the first programme in the series, the Extreme Archaeology team tackled the River Wye, on the English-Welsh border, to identify a mysterious structure that has been puzzling locals and archaeologists for years.

Located just upstream from Chepstow Castle, a square timber and stone platform is visible at low tide, standing in mud flats about 80 metres out from the riverbank. It's always been thought to be the foundations of an ancient bridge – possibly medieval, or even older. Locals believe the structure is part of a Roman bridge. Could it even have been the crossing place for the Roman invasion of Wales?

Despite the site having been known locally as 'the Roman bridge' for many years, the platform has never been examined archaeologically. In fact, no archaeologist has ever got a closer view than from the bank, because the River Wye is too fast-flowing and dangerous for swimming or paddling. With the second largest tidal range in the world, the river can rise and fall by more than 12 metres, and at low tide the mud flats are deadly, sucking in anyone that dares to venture onto them.

The archaeological mission for the Extreme Archaeology team was to reach the structure in the middle of the river, record it and extract a sample of wood for tree-ring dating. It was a high-risk challenge: the team could only work for one hour, twice a day, at low tide, and there was a real danger of drowning if any of them got stuck in the mud.

But the archaeologists felt it was worth the risk. If it could be shown to be Roman, the structure would be the first evidence that the Romans crossed from England to Wales at Chepstow, and would be one of only 35 wooden Roman bridges known in the world.

Partially filmed using small cameras attached to the archaeologists themselves (see Filming it), the programme brings the audience nail-bitingly close to the team members as they struggled to achieve their archaeological goal. We see them waist deep in mud, dangling on zip wires and working in drysuits in blisteringly hot conditions (the programme was filmed during the summer heatwave of 2003). It's a race against time as each tide reveals and then swamps the archaeology, and potentially the archaeologists as well.