The Peel Towers are a series of small fortified tower-houses built on the border between Scotland and England in the late Middle Ages. They also functioned as watchtowers that lit fires as signs to warn of possible dangers. A parliamentary act of 1455 forced the towers to have the necessary material for these signals.
A line of these towers was built in the 1430s in the Tweed River valley, from its source to Berwick-upon-Tweed, in response to the potential danger posed by English marks. In turn England built towers in Northumberland, Cumberland, Westmorland and North Yorkshire for fear of Scottish invasions. Gallery
wiki
