In 70 AD the Romans laid siege to Jerusalem. The most fearsome weapon in their armoury was a massive torsion spring catapult that towered more than 8 metres high. It could fire boulders weighing 26 kgr to destroy Jerusalem’s walls and was so powerful that only the Roman Army’s elite 10th legion had the skill to build it. Now an international team of engineers and scientists try to recreate the most complex Roman war machine. The Romans built catapults for over 200 years and Roman eye witness accounts tell of how devastating the monster catapult was –and how it was capable of killing their own men as well as the opposition if even the smallest detail was wrong. Our team has just 10 days to build the giant catapult from scratch and fire a missile –without killing any of their own team. Will they suceed?