A particularly fine stretch of the the vallum can be found running to the south of Hadrian’s Wall at Cawfields (MC42). The photograph shows the line of the flat-bottomed ditch with the two banks on either side.
One of the most surprising Roman monuments is the ‘turf’ Antonine Wall that stretches effectively from the Firth of Forth to the Clyde. One of the best preserved sections is at the Roman fort of Rough Castle (near Falkirk). As you look northwards you get a sense of the edge of empire (though, of course, the network of Roman forts stretches northwards).