Devil's Highway (Roman Britain) From Calleva, this road divided into routes to various other points west, including the road to Aquae Sulis (Bath); Ermin Way to Glevum (Gloucester); and the Port Way to Sorviodunum (Old Sarum near modern Salisbury). After the Roman conquest of Britain in 43 AD an earlier Iron Age settlement developed into the Roman town of Calleva Atrebatum. It was slightly larger, about , and was laid out along a distinctive street grid pattern. The town contained a number of public buildings and flourished until the early Anglo-Saxon period. A large mansio was situated near the South Gate, consisting of three
Aphanizomenon flos-aquae toxic chemicals released when cells die. Once released (lysed), and ingested, these toxins can damage liver and nerve tissues in mammals. In areas where water quality is not closely monitored, the World Health Organization has assessed toxic algae as a health risk, citing the production of anatoxin-a, saxitoxins, and cylindrospermopsin. Dogs have been reported to have become ill or have fatal reactions after swimming in rivers and lakes containing toxic "A. flos-aquae". Microcystin toxin has been found in all 16 samples of "A. flos-aquae" products sold as food supplements in Germany and Switzerland, originating from Lake Klamath: 10 of 16