Green masses in ditches and ponds are often caused by networks of long threads originating from filamentous algae.

Cyanobacteria or blue-green algae are undoubtedly the most important microorganisms that have ever appeared on Earth. Here you can read more about these fascinating microorganisms.

It is not that often that I look at blood under the microscope. It usually happens when I get injured and have the opportunity to get a microscope. After an unfortunate shave, I act quickly so that I can prepare a slide from the blood before it dries up.