Two hundred people have packed a public inquiry into plans for a controversial road tunnel close to Stonehenge.
Stonehenge's current setting: "a national disgrace"
The scheme involves removing the A303 road from the protected World Heritage Site in Wiltshire and boring a 2.1km (1.3 mile) tunnel underneath.
The inquiry at Salisbury's Guildhall, which is expected to last until 30 April,opened with the inspector, Michael Ellison, outlining the plans.
He went on to list witnesses to appear and describe the inquiry structure.
At the end of the inquiry, Mr Ellison will decide whether to recommend the seven orders proposed by the Highways Agency to the secretaries of state, with or without modifications.
Later on Tuesday, the Highways Agency started presenting its points in favour of the £193m government-approved scheme to widen and conceal the A303 under Salisbury Plain.
The road becomes clogged with traffic during the tourist season, carrying between 22,000 and 33,000 vehicles each day.
Opening the agency's case, barrister Charles Calvert said the plan was "no ordinary road scheme" and that the site's current setting had been described as a "national disgrace".
He went on to stress the proposed solution was as a result of an "innovative approach" by the Treasury allowing the Department for Culture, Media and Sport to contribute towards the scheme.
"This is an opportunity that, quite simply, must not be lost," he told the hearing.
Objectors - such as the National Trust, The Campaign to Protect Rural England and Friends of the Earth - say the tunnel should be longer to conserve and enhance the Neolithic site.
Those in favour of the proposed tunnel will give evidence and be cross-examined before opponents of the plan make their case.