Public bathing 19 BC had a rotunda 25 metres across, circled by small rooms, set in a park with artificial river and pool. By AD 300 the Baths of Diocletian would cover , its soaring granite and porphyry sheltering 3,000 bathers a day. Roman baths became "something like a cross between an aquacentre and a theme park", with pools, game rooms, gardens, even libraries and theatres. One of the most famous public bath sites is Aquae Sulis in Bath, England. Dr. Garrett G Fagan, a professor at Pennsylvania State University, described public bathing as a "social event" for the Romans in his
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