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.
Nothing of the fort can be seen from but traces of the mound are visible in the field beside the fort.
Links: www.antoninewall.org, en.wikipedia.org