Visit the Research Adit and get one of the Minigolf holes. And, by the way, see the ferns reflected on the walls, whose greatest bloom was during the so-called “ferns”. Carboniferous period, or Carboniferous. At that time, the climate was very humid and warm, and there was a lot of carbon dioxide in the air. Ferns include three clusters: ferns, horsetails and forbs. It’s amazing, but in the Carboniferous period their size reached 30 meters.