It might sound a bit cramped, but there's an entire world of organisms that can call a drop of water their home. And, up close, they look practically out-of-this-world. Each year, the Nikon Small World competition sets out to collect some of the best microphotography. Take a look at some of this year's most stunning images of creatures that live in water. This photo from Dr. Jan Michels of Christian-Albrechts-Universität zu Kiel in Kiel, Germany shows Temora longicornis, a marine copepod, from its ventral view at 10 times magnification.

SEE MORE PHOTOS: It's a Nikon Small World After All

This microphotograph shows the diatom Melosira moniliformis at 320 times its size.

This algae biofilm photographed up-close makes what's usually referred to as "pond scum" look like art.

This Philodina roseola rotifer was alive and well when this microphotograph was taken.

This microphoto shows a water flea flanked by green algae.

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Warfare in a water droplet! This microphoto shows a Hydra capturing a water flea at 40-times magnification.

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One of the ultimate human pests -- the mosquito -- begins life as larvae, here shown suspended in a single droplet of water.

Ever wonder what sex between two freshwater ciliates looks like magnified at 630 times its actual size? Now you know!

This freshwater water flea is shown at 100 times its actual size.

Closterium lunula, a kind of green alga, is shown here. This particular specimen came from a bog pond, according to the photographer.

While it may resemble a visitor from outer space, this is what a zebrafish embryo looks like under a microscope, three days after being fertilized.

This microscopic crustacean appears yellowish-orange because it is mounted in Canada Balsam with crystals and other artifacts.

A white-spotted bamboo shark's embryonic pectoral fin makes for a stunning image under a microscope.

SEE MORE PHOTOS: It's a Nikon Small World After All