The Antonine Wall was built by the Romans across what is now known as the Central Belt of modern-day Scotland. The wall was 63 kilometres (39 miles), was about 3 metres (10 feet) high and 5 metres (16 feet) wide. Construction began in AD 142 and took 12 years to complete.
Although there are no visible remains today, the fort was situated on the east slope of the hill and offered some of the best views looking down along the wall.
Links: www.antoninewall.org, en.wikipedia.org