Happy Earth Day! Happy Birthday, Mother Nature!

Or perhaps, Happy Day of Our Precious, Pale Blue Dot. The blue that blankets our home is its defining feature from billions of miles away and, often, the defining feature of our daily lives -Earth Day and every day.

To be sure, our slippery relationship with water—an endless need, and for some a constant struggle—received its due a few weeks back with World Water Day's unprecedented slate of activities, outreach, and partnerships. A gorgeous special edition of National Geographic landed on many doorsteps, filled to the brim with details of the challenges posed by a lack of water, the dangers of our conspicuous consumption—and, of course, unforgettable images that say far more than fleeting words.

So many of us enjoy the privilege of a clean tap just footsteps away, a daily shower, soap and warm water—without so much as a second thought, often barely even a first one. Yet clean water consumes not just the thoughts but most of the waking hours for nearly a billion of our fragile planet's fellow inhabitants. Can you imagine the joy of an ice cube? Recalling life as a Lost Boy of Sudan (What Is the What), memoirist Valentino Achak Deng told of unbridled glee among young boys at a refugee camp in Kenya holding their first piece of ice—some a little frightened, it was so alien.

The challenge of clean water for all is daunting, but that hasn't stopped intrepid intellects from seeking answers. Alongside the resilience of women who spend their lives beholden to jerry cans and shrinking wells are exciting ideas springing forth to solve the problem in simple, affordable, and sustainable ways. A portable, battery-powered electrochlorinator, for example, could treat water for an entire community.  In areas where agriculture is over-extending the water table, channeled rainwater is helping to re-charge aquifers. Recognizing the potential of private markets in meeting public health needs, PATH's Safe Water Project is evaluating the best home-based products that can be made available at realistic prices and then determining the most promising channels for bringing them to market.

Today, and all days, we should not consider our relationship to Earth without closely examining our relationship to water—and to each other. We must remember how the health of our planet remains intrinsically linked to the health of its people. And, to borrow the eloquence of Carl Sagan—who coined an unforgettable epithet for our unique, collective home—we must “preserve and cherish the pale blue dot.”