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From Pecunia Non Olet to Sustainable Sanitation

Even ancient Rome proves that one person’s waste is another’s resource. Emperors have always needed money, and Vespasian (AD 69–79) turned a stinky problem into tax revenue. Public latrines collected gallons of urine rich in ammonia, which tanners and fullers used to soften hides and bleach togas. When his son Titus balked at taxing human waste, Vespasian famously held a coin under his nose: Titus smelled nothing – “money does not stink,” the emperor quipped. The tax on vectigal urinae (urine duty) coined the phrase pecunia non olet (“money doesn’t smell”). It was an early lesson that in a money-driven world, value can come from the foulest sources. With an environmental twist, this odd chapter has modern resonance. After all, we still flush away mountains of pee and poo: an average person produces about 128 g (4.5 oz) of feces and 1.42 liters (48 oz) of urine daily . Multiply that by today’s ~8 billion people and it adds up fast – on the order of billions of tons of solid waste an...
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Magnesium and Your Health: How Much You Need, and What to Eat

Magnesium often flies under the radar, even though it quietly supports over 300 chemical reactions in our bodies (like energy metabolism, muscle and nerve function, and even DNA replication). With such wide-reaching impacts, it’s surprising how easy it can be to fall below recommended levels without realizing it. Why magnesium matters—for you and nature Magnesium isn’t only something our bodies need—it’s something plants need, too. In fact, without magnesium, they can’t make chlorophyll, which is what helps them soak up sunlight and grow. If you've ever had a houseplant with yellowing leaves, low magnesium might’ve been the culprit. Out in the fields, it’s the same story. If the soil doesn’t have enough magnesium, crops don’t grow as well. And if crops aren’t healthy, they’re not as nutritious for us when we eat them. So really, magnesium connects us—from the soil, to the plants, to our plates. How much do we actually need? The U.S. Institute of Medicine sets daily targets for ad...

From Population Explosion to Decline: How the World Reached 8 Billion—and What Comes Next

Back in the 1960s, many scientists and policymakers feared the world was heading for disaster—not because of climate change or artificial intelligence, but because of too many people. Paul Ehrlich’s 1968 bestseller The Population Bomb warned of mass starvation and ecological collapse if human numbers weren’t brought under control. These fears shaped national policies, global aid, and even coercive sterilization programs in some countries. And the numbers did seem alarming. The global population rose from 3 billion in 1960 to 5 billion by 1987, then to 6 billion by 1999, and 8 billion by 2022. Since the mid‑1970s, we’ve been adding about 1 billion people every 12 years. The animated map below, created by VividMaps.com using World Bank data, shows how population changed in each country from 1960 to 2022: The map makes it clear: Asia has long led the world in population size, growing from about 1.7 billion in 1960 to 4.7 billion by 2022. Africa’s population grew even faster—up nearly six...

How Long We Live: A Global Story of Life, Health, and Change

Ever wondered how long the average person lives these days—and what those years actually look like? Life expectancy isn’t just a number. It’s a mirror of how well a society supports its people—from access to clean water and doctors to education, air quality, and even peace. And the global story? It's been one of steady progress, despite a few hard-hitting setbacks. Between 2000 and 2019, the average life expectancy across the world rose from about 66.8 years to 73.1 years, according to the World Health Organization. That’s over six extra years in less than two decades. Pretty impressive, right? But then came COVID-19, which knocked that number back temporarily. Even so, most of the long-term gains have held strong. Meanwhile, something called healthy life expectancy—basically, how many of those years we live in good health—has also gone up. People aren't just living longer, they’re living better, too. Where People Live the Longest Some places seem to have cracked the code. Ti...

Elephant Diversity and Conservation: Habitat, Species, and Survival

Elephants are amazing creatures, but their world is changing fast. A 2023 map by cartographer Wanmei Liang brings this into focus: it marks every elephant species and subspecies in a different color. (The source data comes from the Elephant Territories project.) In Africa, two species remain : the savanna (bush) elephant and the forest elephant. In Asia, there’s one species – the Asian elephant – split into three main subspecies (Indian, Sri Lankan, and Sumatran). The map shows African savanna elephants in purple, forest elephants in red, Sri Lankan elephants in pink, Indian elephants in orange, and Sumatran elephants in yellow (a lowly known subspecies of  Indian elephants of the Borneo elephants is not shown on the map). This visual makes it easy to see where each lives and who they are. In real numbers, all elephant groups are dwindling. Across Africa, an estimated about 400,000–415,000 elephants survive today. Most live in East and Southern Africa (Botswana, Tanzania, Kenya,...

The Hidden Truth About American Life Expectancy

Most people don't realize that turning 75 in America actually means you'll probably live way longer than anyone expected when you were born. The latest Social Security data from 2024 shows a 75-year-old man will likely make it to 86. That's a full 12 years past the original life expectancy of 74. Why does this happen? It comes down to how statisticians crunch these numbers. They take 100,000 hypothetical people and apply real death rates at every age to see who survives year by year. The average age at death becomes the " life expectancy at birth " — but here's where it gets interesting. As Harvard research explains, older adults have already navigated past the biggest risks: infant mortality, accidents, and violence. Think of it like climbing a mountain. The higher you get, the better your odds of reaching the summit become — not because the climb gets easier, but because you've already proven you can handle the difficult terrain below. The numbers tell...

Barbie’s Feet Are Getting Flatter—And It Says a Lot About Us

Barbie’s arched feet have long been a part of her image—tiny, pointed, and forever perched for stilettos. But that’s starting to change. A new study reveals that Barbie’s feet are flattening, and that shift isn’t just about doll design—it reflects a broader change in how we think about women’s fashion and comfort. A team of podiatrists at Monash University analyzed 2,750 Barbie dolls produced between 1959 and 2024. They found that while every single doll in the 1960s had permanently arched feet made to fit high heels, only about 40% of Barbies in the 2020s still have that same foot shape. This shift isn’t random. It follows Barbie’s growing list of careers—astronaut, firefighter, doctor—where practical shoes make a lot more sense than stilettos. This change was even acknowledged in the 2023 Barbie movie. In one early scene, Margot Robbie’s Barbie steps out of her heels and her feet stay arched, just like the classic dolls. But later in the film, her feet flatten out, a visual cue ...