The centre has cost £22m to build in a disused quarry
The world's biggest indoor climbing arena, being built just outside Edinburgh, is set to transform Scotland's access to adventure sports, according to developers.
The Ratho Adventure Centre, due to open in September, is expected to to attract up to 200,000 visitors a year.
The climbing hall itself will be the largest indoor arena in the east of Scotland and is the world's biggest indoor climbing arena.
It is hoped the complex, which is costing £22m to construct in a former quarry, will become a centre for world climbing, hosting a string of international competitions.
Duncan McCallum, of Ratho Adventure Centre, said it was "the largest investment in adventure sports in Europe in recent years".
'Gateway to adventure'
He added: "The site was completely filled with rubble about four years ago.
"Since then we've removed 250,000 tonnes of rock and stone.
"It is by far the biggest climbing arena in the world and is by far the biggest gateway to adventure sport that the UK will ever see I hope."
The 120,000 sq ft complex has been set into the quarry itself and contains climbing walls over 100ft high.
The centre is scheduled to open in September this year
A stretch fabric roof, similar to that used on the Edinburgh's Dynamic Earth attraction, has also been lowered into place.
Scot Malcom Smith, a world championship climber, said the centre has "the best climbing wall I've ever seen".
He added: "It's totally world class. It's going to be really good for Scottish climbing and is going to bring the sport on a lot.
"I'm sure in a few years we will see a lot of world class climbers coming to Scotland."
The adventure centre will also be a stepping stone to other high-adrenaline sports.
As well as climbing facilities, it will include the Scottish Judo Federation's National Academy, BMX and mountain bike trails, a scuba dive school, a health spa and a 200-seat lecture theatre.
There will also be accommodation for 90 people and a wide range of additional sports and fitness facilities.