A controversial plan for a road tunnel past Stonehenge has been finalised by the government.
Campaigners claim the 1.8-mile (2.9 km) dual-carriageway tunnel will cause "irreparable damage" to the landscape.
However, Transport Secretary Chris Grayling said the plan will "transform" the A303, "cutting congestion and improving journey times".
A public consultation to get the views of drivers and residents will run until 5 March.
The busy A303 currently passes within a few hundred metres of the ancient monument.
The tunnel forms part of a £2bn government scheme to upgrade all remaining sections of the road between the M3 and M5.
However, campaign group Stonehenge Alliance believes any tunnel shorter than 2.7-miles (4.3 km) would do "irreparable damage to the landscape".
Chairman of Amesbury Museum and Heritage Trust, Andy Rhind-Tutt, described the tunnel plan as a "self-destructing time bomb" which would "do nothing" for traffic problems in the area.
In 2015, a Stonehenge Alliance petition calling for a longer tunnel gained 17,500 signatures.
In a statement, the group said: "The Alliance does not advocate new road building at Stonehenge, but accepts the need to improve the tranquillity and appearance of the World Heritage Site and its setting.
"If the government insists on widening the A303 by means of a tunnel, it must be sufficiently long to avoid any further damage to [Stonehenge] and its setting."
English Heritage and the National Trust have also given their support to the option of "the longest tunnel possible".
Highways England's Jim O'Sullivan said: "Our plans for the A303 recognise the national importance of the route and these improvements will bring real benefit to the region and local communities.
"The public exhibitions will provide an excellent opportunity to explain further our plans and to hear feedback from stakeholders."
Stonehenge is one of the Europe's most recognisable prehistoric monuments.
The history of the Wiltshire site dates back 4,500 years and it is the only surviving lintelled stone circle in the world.
A report by UNESCO and the International Council on Monuments and Sites has recognised the benefits of the project.