Calleva Atrebatum 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). The earthworks and, for much of the circumference, the ruined walls are still visible. The remains of the amphitheatre, added about AD 70-80 and situated outside the city walls, can also be clearly seen. The area inside the walls is now largely farmland with no visible distinguishing features, other than the enclosing earthworks and walls, with a tiny mediaeval church in one corner. There is a spring that
Aphanizomenon flos-aquae samples exceeded the safety value of 1 µg microcystin per gram. University professor Daniel Dietrich warned parents not to let children consume "A. flos-aquae" products, since children are even more vulnerable to toxic effects, due to lower body weight, and the continuous intake might lead to accumulation of toxins. Dietrich also warned against quackery schemes selling these cyanobacteria as medicine against illnesses such as attention deficit hyperactivity disorder, causing people to omit their regular drugs. A Canadian study studying the effect of "A. flos-aquae" on the immune and endocrine systems, as well as on general blood physiology, found that eating