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 (dietary supplement) from the air, and water to synthesize proteins, carbohydrates, and lipids. AFA is also able to directly use molecular nitrogen from the air to produce proteins and other nitrogen-containing biomolecules. This ability is widespread in prokaryotes, but unknown in eukaryotes. "Aphanizomenon flos-aquae" as a species has both toxic and non-toxic forms. While benefits have been indicated, toxicity has been shown in some strains of the species "Aphanizomenon flos-aquae", with cylindrospermopsin and saxitoxins present, and microcystins found contaminating AFA dietary supplements. The World Health Organization's "Guidelines For Drinking Water Quality" note Anatoxin-a, saxitoxins, and cylindrospermopsins are present in the Aphanizomenon genus.