Adam Hart-Davis rediscovers the innovations and inventions the Romans brought to Britain. Following in the footsteps of the advancing Romans, Adam reaches Hadrian's Wall--the monument that marked the northern edge of the empire for 300 years. Here he shows how communications were key to the success of the Roman military machine. 2,000 years before mobile phones and the Internet, soldiers used codes similar to today's digital signals to send messages utilizing flags and beacons. In a remarkable experiment, Adam shows how they did it. He also reveals the Roman equivalent of postcards in extraordinary writing tablets found at the fort of Vindolanda. They give a glimpse of life in the north--from shopping lists to party invitation--and Adam tries to find out why the ink didn't smudge on the delicate wooden tablets.