George Washington never liked the name of the American capital that was being built on a swamp in the 1790s. He was too modest to appreciate the name Washington City, as it was called. He saw the fanfare more befitting a monarchy than a constitutional democracy. So one can imagine his discomfort at the giant obelisk later built for him, still towering two centuries after he died in 1799.

The Washington Monument has become the physical symbol of America's separation of powers. In Washington D.C., it sits at the center of the people's congress, the highest court, the president's mansion, and the memorials for two other presidents, Lincoln and Jefferson. The structure has been ...

About a year ago, during a trip to Reykjavik, the capital of Iceland, I had the strange and rare experience of emailing a head of state, being invited over for coffee, and knocking on her front door. That’s just Iceland, people told me. You can look up anyone in the phone book, even the president. These days, Vigdís Finnbogadóttir is a former head of state in semi-retirement after sitting in office from 1980 to 1996.  As we talked, I asked her one of the most softball questions in politics:

“What would you say was your biggest accomplishment as president?” I said.

Without even ...

Every few months, a new report on climate change comes out that spells doom for the future of the planet. Sometimes it’s from the International Panel on Climate Change. Sometimes it’s the U.S. Environmental Protection Agency. Just as often, individual scientists present their papers and studies at conferences.

The news is almost never good, Elizabeth Kolbert, the environmental scribe and thinker, has observed over years writing about the planet. Every year, scientists warn time is running out to reel back emissions. And each year, the world emits about three to five percent more greenhouse gases. In the western nations that burn the most fossil fuels, what needs ...

The biggest barrier to innovation is sometimes the fact that it’s cheap enough to do things the old way. Why develop new foods when the old ones are popular? Why create new cars when existing ones fit everyone’s needs?

That rationale is particularly true at the moment for energy, and especially gasoline. As environmental groups call for cleaner and more sustainable ways to produce energy, the inconvenient fact is that fossil fuel is cheap. Natural gas continues to be found in great abundance. And for much of 2014, as a result of booming supply and advanced technology to drill in more remote places, oil prices have cratered, reaching their lowest ...

For a supermarket to look clean, fresh, and full, a complex equation needs to be constantly balanced. Food needs to be grown on time, shipped on a deadline, and purchased wholesale at the peak of perfection. If any piece doesn’t fit, things fall apart. That equation helps determine the price of food which, if we’re lucky, doesn’t fluctuate dramatically. Sometimes I buy overpriced orange juice, sometimes I get it on sale. Over time, for most of us, it evens out.

But over the long term, how is the price of food changing? This week, in observance of Thanksgiving, the American Farm Bureau Federation has an answer: if you account for inflation, ...

Last spring, we took an unconventional road trip. An NG photographer and I followed a truck of strawberries across the U.S. in three days, from California to Washington, D.C., to understand what it takes to deliver food grown thousands of miles away. The story appeared online, and in the November edition of National Geographic Magazine.

We received several questions about the trip, like why we chose to follow strawberries (they're a classic American food, agriculturally isolated, and extremely fragile) and whether the truck drivers knew we were behind them (yes, and they even slowed down for us).

But one question was more complex. From John Daly in Chelsea, Michigan:

"Why did the truck travel ...