BBC Four HD Schedule, Today (United Kingdom)

In a world exclusive, Professor Alice Roberts follows a decade-long historical quest using cutting-edge research that reveals Stonehenge's oldest secret. [S,AD] [HD]

2/2. Michael Scott continues his journey through Sicily, tracing the island's story through the arrival of the Muslim Arabs and then the Normans. [S,AD] [HD]

Martin Shaw separates the fact from the myth as he takes to the skies to retrace the route of the 1943 raid by 617 Squadron which used bouncing bombs to destroy German dams. [S,AD,SL]

Programmes start at 7.00pm. [HD]

Programmes start at 7.00pm. [HD]

3/3. Barra Best explores some of Northern Ireland's lost railways. In this episode he hears how the Fermanagh railways were used in a game of wartime espionage, and visits the barbers. [S] [HD]

2/5. Life on England's waterways with Robbie Cumming. A low canal tunnel in Staffordshire proves a problem, and Robbie helps out a stranded boater. [S] [HD]

8/10. Michael Palin takes a reed boat on Lake Titicaca in the Andes before embarking on a 1,000-mile journey along the Urubamba river to the Amazon. [S]

Natural history short. Newborough forest, on the edge of the west coast of Anglesey in north Wales, is home to one of the biggest raven roosts in Europe. [S]

...Andrew Marr's Paperback Heroes. 1/3. Andrew Marr investigates detective fiction, and reveals how it works. [S,AD] [HD]

Actor Trevor Eve, who played Detective Superintendent Peter Boyd in all nine series, looks back at the long-running BBC crime drama Waking the Dead. [S] [HD]

1/8. When Detective Superintendent Boyd encounters a woman unable to accept the explanation of her father's death in a terrible car crash, he takes on the case. [S,AD]

2/8. New evidence points to suicide but, when Boyd and the team exhume Perry Coleman's body, DNA tests reveal some disturbing facts that call this into question. [S,AD]