2/10 Scientists achieve a world first, finding and filming the impossible - a giant squid. (R)
2/4 The stories behind the steam locomotive, internal combustion engine and the jet engine. (R)
3/4 The stories behind the electric telegraph, the telephone and wireless communication. (R)
Claudia Hammond revisits Langer and Rodin's 1976 Arden House study.
BBC Radio 4 Extra
19/25 Council officers get their hands dirty to preserve a prized park. (R)
7/10 The team respond to reports of two men fighting with knives. (R)
20/25 The council hunt down any unwanted residents lurking in the town centre.
Philip Hoare attends the necropsy of a porpoise and thinks about going inside a whale.
BBC Radio 4 FM only
Na Gearmailtich a' gèilleadh ris na feachdan aig an Seanaral Louis Botha ann an Afraga. (R)
BBC Radio Nan Gàidheal