A group of schoolchildren are to be the first to put a new multi-million-pound tourist attraction through its paces.
The £3.3m Alnwick Garden tree house in Northumberland officially opens to the public on Wednesday.
But the Duchess of Northumberland, who has spearheaded the project at Alnwick Castle, has invited 30 local youngsters to a VIP event on Tuesday.
The 60ft high complex, complete with turrets is expected to be one of the north's biggest visitor attractions.
Built around 16 mature lime trees, with suspended walkways accessible to wheelchair users, it houses a shop, toilets, reception area and cafe.
The tree house project is part of the redevelopment of the castle's gardens into a major tourist attraction.
At the base of the tree house a huge play area is being developed.
The Duchess said: "Many children now have less opportunity to play than any other generation.
"We have wonderful plans to expand our facilities.
"The idea is to provide a challenge, and include elements of risk, so that you help children better equip themselves for the future."