The Pio XI Glacier is the most active tidewater glacier in Chile. She is three miles wide and somewhat over 100 feet high. Unlike her sisters, she is advancing. We spent the early morning exploring in Zodiacs, cruising about her beautiful children, each unique as snowflakes. There were blues and whites, transparent crystal and hard green glass, with sharp edges and smooth contours.

We saw faces and bodies, long-necked swans that changed to bears or then again to fierce dragons as we drifted past and shifted our perspective. The sea was milky with glacial flour; bits of finely chewed-up rock suspended in a lens of fresh water floating on the denser salty sea. At times we slowly pushed our way through brash ice, bits of bergs that tumble beneath the Zodiac.

Among the floating ice there was the constant sound of popping and cracking as pockets of pressurized air burst from gelid cells of weakened crystal, air that might have last been breathed by the earliest people to settle here thousands of years ago.

Occasionally, in the distance, there was a sharp report, a powerful reverberating boom. At a mile away it was impossible to pinpoint the source; at a half-mile though we learned the truth: it was the announcement of a birth, the creation of fresh new bergs. Mighty towers of ice would suddenly lurch, shatter, and plunge into the sea with a mighty splash of muddy water, sometimes reaching over fifty feet in the air.

Often we were lucky and the first birthing was followed by another and yet another. Each calving brought a rolling swell that gently rocked the Zodiacs and caused the nearby drifting ice to shift and sparkle. From here the glacier seemed a living thing, a being so huge and grand that we were beneath her notice while she sent her children seaward, to slowly melt and die, transient bits of beauty to be enjoyed by all, or perhaps most importantly, even by none at all.