For courage, says Bulgarian folk wisdom instructs, keep a horse chestnut in your pocket.Even as a child, I was mistrustful of superstition. But every autumn, I would pick up dozens of them from the sidewalks of Sofia and fill my pockets — not as a spell against fear but as an ode to joy. Conkers, as the English call them, spun me up in delight — shiny as mahogany, smooth as river stones, tiny planets from some other universe, the wonder-smitten eyes of some prehistoric creature. I didn’t know then that they are emblems of life’s irrepressible insistence on itself — miniature monuments to the stubborn creativity of survival. Illustration from Die Baume und Straucher des Waldes by by Gustav Hempel and Karl Wilhelm, 1889.Three million years ago, as the Ice Age was beginning to sink its cool blue fangs into the warm body of Earth, the widespread horse chestnut (Aesculus hippocastanum) began dying off, until only a small population remained, most of it sheltered in the gorges of Bulgaria’s mountains. There, in their sanctum of stone, the trees found themselves unable to attract pollinators during the slender three-week window of their flowering. This is the story of life — innovate or die: The horse chestnut evolved enormous white flower spikes with pink tips and a chemical hack to block the oxidation of polyphenols in the petal, which turns each flower brown and sheds it after pollination. For three whole weeks, the horse chestnut remains a bride in a gown of amazement, its crown an aria of perfect white blossoms that no bee can resist, all because there was a safe place in which to experiment with the possible. Illustration from American Medicinal Plants by Charles Frederick Millspaugh, 1887.That place, I learn from my poet friend Hannah Fries’s absolutely wonderful book A Forest Language, is called refugium. Hannah writes:When glaciers last crept down from the Arctic, 20,000 years ago, there were places where the icy fingers didn’t reach — mountaintops, hot springs, lowlands beyond the ice. There were pockets of green where things crawled and slithered and ate and mated, protected places where life went on, and from which life set forth again as the ice receded. Refugia.[…]The gift of a refugium is time. It holds in its small cup of safety a promise for a new world to come. And it lends out to the living all the years, centuries, millennia it might take to finally find that world.Even in easier times, it is wise to tend the refuge. What is Earth, after all, but a momentary refugium in the inhospitable blackness of space? From a vantage point far beyond our grasping glows the blue-green dot, a brief and luminous memory in the mind of the universe. It is the memory of a place where a simple cell had the ambition to harness the energy of a star, and from it, the green wonder of leaves, the trunks rising up, bursting and blooming into the sky — all of life in the sweet, cool shade below.We too need them, these refugia that shelter us, that save us in the ice ages of life. Whatever your refugium may be — a place, a person, a practice, a poem — it is worth tending to with all the might and all the means you have. donating = lovingFor seventeen years, I have been spending hundreds of hours and thousands of dollars each month composing The Marginalian (which bore the outgrown name Brain Pickings for its first fifteen years). It has remained free and ad-free and alive thanks to patronage from readers. I have no staff, no interns, no assistant — a thoroughly one-woman labor of love that is also my life and my livelihood. If this labor makes your own life more livable in any way, please consider lending a helping hand with a donation. Your support makes all the difference.newsletterThe Marginalian has a free weekly newsletter. It comes out on Sundays and offers the week’s most inspiring reading. Here’s what to expect. Like? Sign up.