<human>:  Who was the first person to see bacteria with a microscope?
<bot>: Antonie van Leeuwenhoek was the first person to see bacteria with a microscope. In 1676, he used a microscope to observe what he thought were animalcules, or protozoa, in water samples. He was actually observing bacteria, but at the time, scientists thought that these small organisms were protozoa. He was the first person to observe bacteria with a microscope, and he made many other important discoveries.