A glacial torrent pours over a 40-foot-high ledge at Gođafoss, "waterfall of the gods." After the Icelandic assembly adopted Christianity in 1000, its leader threw his pagan idols into the falls. The mossy island, notes geographer Guđrún Gísladóttir, "is protected from sheep."
At Hveravellir—literally "hot springs in the plain"—thin terraces of geyserite precipitate from the water as it cools. A notorious 18th-century outlaw, Fjalla-Eyvindur, stayed warm here for years, stealing sheep from summer pastures.
United States—On Massachusetts's Plum Island, a piper plover plumps for one of its primary roles following the hatching of its chicks: warm cover. Though able to feed on their own within a few hours, the fledglings need help maintaining their body temperature.
When Hverfjall erupted 2,500 years ago, no one saw it—no one lived in Iceland. On a March evening photographer Orsolya Haarberg watched alone as a north wind scoured Mývatn lake's thin ice, sweeping snow into a drift that looked like a path to the crater.
Herodotus called Egypt the "gift of the river" because the country would be a sandy wasteland without the Nile's nourishing waters.
United States—A dead athel tree, bathed in moonlight in a long night exposure, attests to former fertility on what is now a salt pan at the edge of the Salton Sea. Salinity at the California lake, 231 feet below sea level, is some 50 percent greater than the Pacific Ocean's.