For the past four decades the Nikon Small World competition has placed photography under the microscope, with eye-catching results. This year’s 20 finalists, announced Thursday, are no exception, zooming in on microorganisms, minerals and even electronic circuitry to find beauty hidden from the naked eye.

Judges evaluated more than 1,200 photos sent from dozens of countries based on scientific relevance, composition, quality and technique, along with technical and artistic merit. The competition’s subject matter is unrestricted as long as some type of light microscopy technique is used, including phase contrast, polarized light, interference contrast, dark field or some combination thereof.

First prize is $3,000 toward the purchase of Nikon equipment. Past winners have taken the prize using subjects including colorful freshwater diatoms and menacing insect larva that could serve as inspiration for a Halloween costume.

The following slide show features this year's 20 winning pictures.