Most bacteria are so small that under a light microscope you can only see them as little dots.
Some groups however grow to large sizes and have spectacular shapes.
The top picture shows an example of the beauty of one of the more advanced groups of bacteria, the cyanobacteria, or blue-green algae. Like plants they photosynthesize. Bacteria were the most prominent creatures in the early stages of life's history almost 4000 million years until 600 million years ago. Fossils called stromatolites can still be found and were made by cyanobacteria. Cyanobacteria were essential for the developing of more complicated life forms.