Criminologist David Wilson conducts an investigation into the death of Russia's first dictator, who ruled the country during the 16th century. Beginning with rumours that Ivan was strangled by enemies close to him, the historical murder mystery then takes Wilson across Russia and on to the court of Queen Elizabeth I. Forensic science finally reveals the way in which Ivan was dispatched - but who was responsible?

Rome, 81 BC: Sextus Roscius is accused of patricide. If found guilty, he faces a brutal execution. Defending him is a young lawyer - Cicero. Using the actual trial record, this drama reconstructs one of the most celebrated murder trials in history. NEW SERIES 1/5.

When Stalin's death from a brain hemorrhage was announced in March 1953, the true details surrounding his death were immediately suppressed: the Soviet Communist Party's power would crumble if foul play was suspected. Acclaimed historian Simon Sebag-Montefiore plays detective, travelling to Moscow to investigate. For the first time, the content of secret KGB files is examined and the official version of Stalin's death is denounced as lies, while interviews with witnesses and experts present an array of motives and suspects. 2/5.

It's 9am on 20 January 1607: a 12ft-high wall of water devastates the counties of the Bristol Channel, killing in the region of 2,000. The catastrophe altered the coastline for ever - yet it's been all but forgotten. Scientists Ted Bryant and Simon Haslett team up to find archaeological evidence to support their belief that the event was not a freak storm but a tsunami.

A love of bloody spectacle led the Romans to build amphitheatres all over their Empire. In Britain there were at least 25, the largest in Chester where archaeologists Tony Wilmott and Dan Garner spend three months excavating a complex site of ruins. With the help of computer animation, they bring the amphitheatre back to life.

Mount Tambora in eastern Indonesia unleashed the biggest volcanic blast ever in April 1815, a cataclysmic event that could have provoked a change in climate around the world. Thousands starved to death, lurid skies inspired the artist Turner and, out of the freakish cold, Mary Shelley's Frankenstein was born. On opposite sides of the globe, two experts investigate.

In 1605 a group of angry young Catholic men decided to wipe out the monarchy and government by blowing up the Houses of Parliament. To mark the 400th anniversary of the infamous Gunpowder Plot, Timewatch attempts to establish why the conspirators had became so radicalised under the reign of King James I and assesses just how close the plotters came to achieving their aims. 1/4.

A focus on the man responsible for the deaths of almost two million Cambodians. Dramatic reconstructions, the testimony of acquaintances, and the words of the Khmer Rouge leader himself combine to chart his rise to power and his use of terror and hunger to sustain his new regime. 2/4.

On 17 September 1940 a German U-boat attacked the evacuee ship SS Benares en route to Canada, killing 258 of the 401 on board, including 80 of 100 child passengers. Sixty-five years on, those still living recall how they escaped death by hypothermia and drowning. 3/4.

Psychological analysis of the biggest madman of the 20th century. How in 1943, a team of Harvard psychologists arrived at startlingly accurate conclusions from a profile they drew up of the Führer, in a bid to predict his future conduct. 4/4.