Everyone knows that the world is filled with bacteria. It can make you sick, or it can help you to digest your food and generally live life normally. Most people, however, haven’t ever seen a bacterium in real life.

Sure, they have seen pictures of them in science books, but unless you look under a microscope, you haven’t seen bacteria.

Unless, that is, you have spent time in a swamp in Guadeloupe, that is.

In 2009, scientists were studying a swap in this part of the world when they saw something strange. In a statement about the incident, the person who made the discovery, Olivier Gros, said:

“When I saw them, I thought, ‘strange.’ In the beginning I thought it was just something curious, some white filaments that needed to be attached to something in the sediment like a leaf.”

Gros is a marine biology professor at the Université des Antilles in Guadeloupe, so he knows what he is looking for in swaps. He had never seen something like this, though, so he began looking into it.

After a lot of analysis and research, they could confidently announce that what they had found was the world’s largest species of bacteria. This wasn’t done until 2022.

So, how big is this bacterium? An author of the study, Jean-Marie Volland, explained:

“It’s 5,000 times bigger than most bacteria. To put it into context, it would be like a human encountering another human as tall as Mount Everest.”

It is so big that you can see it with the naked eye. You can see it in this video:

Prior to this species, there were ‘giant bacteria’ that were a few hundred micrometers in size, which scientists used to think was approaching the theoretical maximum for how big bacteria could get.

This species was named Thiomargarita magnifica, and it can get up to 2 centimeters in length, with the average sample being around 1cm. For context, there are 10,000 micrometers in a centimeter. So, this bacterium can get up to about 20,000 micrometers in length.

Fortunately, there is no indication that this bacterium has any interest in humans, so it isn’t likely to make you sick.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.