A scrim of seawater rises from blowholes along the coast of Tongatapu—one of 36 inhabited islands in the 170-island archipelago that is Tonga. First settled more than 3,000 years ago, this chain became the anchor for a not-so-pacific domain that by the 13th century may have stretched as far as Samoa and Fiji. In the 1600s, European explorers arrived, followed by missionaries. But now the pressure for change rises from within.

This larval flounder swims with other fish for now, hidden from predators by transparency (the color is an effect of lighting). It will soon be a bottom dweller that shimmies into the sand, gazing upward. Eyes start out one on each side; as the skull develops, one migrates to join the other.

No bigger than a quarter, a Glaucus nudibranch preys on toxic Portuguese men-of-war, appropriating their stinging cells for its own defense. Camouflaged in blue and silver, this sea slug was caught off Hawaii but drifts in mild waters worldwide.

The Messier 101, or Pinwheel, galaxy spins in pixel perfection in the most detailed portrait of a galaxy ever released by Hubble scientists. The image was produced by combining exposures taken by Hubble with others from ground-based telescopes.

Finland—On a window in Kotka, a slightly battered mosquito sits silhouetted against a mosaic of water drops, each reflecting spring sky and the crayon colors of nearby buildings.

Netherlands—To honor 25 years of Terschelling island’s Oerol theater festival, 2,000 people lined up along 25 giant rings of sand sculpted on the beach, in what artist Rob Sweere called “a silent conversation with the sky.”

What looks like a walrus’s grizzled face is actually a lesson in the limits of persistence. As wind scours away surrounding ground, only sandy hummocks anchored by the stubborn roots of arrowweed plants remain. It’s an eerie landscape: the Devils Cornfield. Eventually, winds can carry away so much dirt and moisture that the arrowweed withers and dies (foreground).

At 282 feet (86 meters) below sea level, Badwater Basin is North America’s lowest point. When it floods, the shallow pools evaporate quickly, leaving polygons of mud encrusted with shimmering salts.