On a hill in the centre of Zurich we found the Gessner-Garten. It's a botanical garden named after Conrad Gessner (or Gesner) who lived in the town in the 1500s. He was a naturalist and he published Historiae animalium (in five volumes) that is considered the beginning of modern zoology, He also established a herbarium and part of the Gessner-Garten is based on Gessner's own, with 50 medicinal plants (herbs and shrubs), used by 16th century's healers. We were shocked to see a Variegated Thistle Silybum marianum in the garden! It's a nuisance weed on our farm.