Overgrown, out of bounds, but tantalisingly within reach: Glasgow's Garrowhill Primary was built in a horseshoe shape in 1939, but the urban woodland it clasped had long since become an unusable mess.
That was until a few years ago, when pupils decided they'd had enough of peering longingly at the neglected treasure on the other side of their windows. From their ideas sprang an outdoor classroom with a bridge, a den, a woodland trail and carvings by the children themselves.
Garrowhill won the Sustainable Schools prize at the recent Scottish Education Awards. Visiting judges, after a three-hour tour, were left puffing out in admiration at pupils who were "confident, mature and had an impressive depth of knowledge".
The 400 pupils continue to push ahead with an ever-burgeoning multitude of ways to mend environments local and global, efforts that have reduced the school's energy use by 30 per cent.
After the outdoor classroom, the latest grand plan started life as a passing fancy in a P5 lesson on persuasive writing. The school had derelict land that used to sit underneath temporary classrooms - why not turn that into a "bee meadow", someone mused. Campaigning letters from pupils solicited support from the city council; work starts in earnest next session.
There has been a plethora of green endeavours at Garrowhill: an Eco Schools prom with the Royal Scottish National Orchestra; a stained glass window depicting the woodland; an organic fruit and vegetable garden; gable end paintings to depict the wildlife drawn to the school; a bird- feeding centre tended with help from the RSPB; a safe cycling project run by a parent; fundraisers for Unicef and Water Aid.
Crucially, says headteacher Richard Buchan, "sustainable development learning is set within a stimulating and meaningful context rather than being an extra area to be taught". Education awards judges said that embedding the concept of sustainability in the curriculum had been the "secret to the school's success".
Despite its achievements, judges noted, "this school was not for standing still", and had plans to explore the idea of forest schools and build international links.
That momentum is spilling out into homes, as an older generation gets a crash course in what can be recycled and how to save energy.
"Parents tell us that the children are really teaching them," says Mr Buchan.