If you want to go down another order of magnitude or few, fluorescent microscopy of single-celled organisms is pretty interesting. This collection of images is

If you want to go down another order of magnitude or few, fluorescent microscopy of single-celled organisms is pretty interesting. This collection of images is stunning: https://www.canadiannaturephotographer.com/epifluorescencemicroscopy.html https://www.canadiannaturephotographer.com/epifluorescencemi... These techniques also revealed the sheer scale of microbial life, as even the clearest ocean water from the most remote, nutrient-limited tropical seas will contain as many as 100,000 cells per mL. Below that there are the various viruses that infect or cohabit with these bacteria and small plants and animals, which are invisible to light microscopy.