This story appears in the September 2019 issue of National Geographic magazine.

In hopes of seeing why a peppercorn tastes peppery, Antonie van Leeuwenhoek (1632-1723) soaked one in water and put it under a microscope. The Dutch scientist imagined that its taste came from tiny spikes or darts. Instead, he saw tiny ridged spheres—and tiny moving organisms, the first bacteria ever observed.

Van Leeuwenhoek, aka the father of microbiology, glimpsed a world in the 17th century that photographer-scientist Martin Oeggerli explores today in far greater detail. Oeggerli made images of herbs and spices with a scanning electron microscope, then enhanced the plants’ parts with color. Some of the parts are both factories and silos, containing chemicals that we taste and smell when we use these herbs.

The flavors of herbs are their arsenal. Since prehistoric times, the chemicals of an herb have evolved in response to the threats that the plant must contend with. Some plants are better defended against slugs, others against sheep. In van Leeuwenhoek’s peppercorn, the heat of compounds called piperines discourages insects from eating the plant. In many herbs, we find hints of the species against which the herb protected itself; in others, we still find mysteries.