Composer Iain Chambers takes a sound recording field trip around Orford Ness in Suffolk. This site – an isolated shingle spit on the Suffolk coast – once played a key role in the UK's development of radar and ballistics. Since buying Orford Ness from the Ministry of Defence in 1993, the National Trust's policy has been one of 'managed decline' – these buildings are now overrun by nature. The excitement felt by Bletchley Park's wartime codebreakers was once felt here too: Britain's greatest scientific brains; 400 civilians; the unacknowledged thousands of Chinese migrant workers, were solving a singular puzzle: how to build a nuclear weapon. Bomb-making justified as deterrence. Today, Orford Ness gives an insight into what a post-apocalyptic built environment might look and sound like. Air ducts once used to ventilate missile laboratories now burst open, exposing the packed nests of roosting birds. This programme takes listeners into buildings that are otherwise out of bounds, revealing the abundant wildlife now ruling the roost in the bomb ballistics buildings – we hear seagulls 'playing' the buildings with their cries; bees and skylarks; baby jackdaws duetting with the crunch of gravel footsteps; external metal stairwells transformed into aeolian harps: giant wind chimes peacefully intoning their pentatonic melodies towards the slow-moving vessels on the horizon. Producer: Iain Chambers An Open Audio production for BBC Radio 3