This close-up view of a human skin cell won first place in the annual Nikon Small World Photomicrography Competition. Dr. Bram van den Broek of the Netherlands Cancer Institute came across this peculiar cell while studying keratin, an important structural protein in skin cells. This cell is expressing an excessive amount of keratin.

"The expression patterns of keratin are often abnormal in skin tumor cells, and it is thus widely used as a tumor marker in cancer diagnostics," said Dr. van den Broek.

Science and art meet under the microscope in the Small World contest and entries are evaluated on technical proficiency, informational content, and visual impact.

Scroll through to see the top 20 winners in this year's contest.