The Pyramid of Cestius
A 2000-year-old pyramid in the city of Rome has been restored by archaeologists
A Though Rome draws tourists from around the world to its many impressive sites, one notable monument there has never attracted nearly as much interest: The Pyramid of Cestius. But why would there be a pyramid in Italy? After the Roman conquest of Egypt in 30 B.C., Egyptian architectural style became the fashion in Rome. Though obelisks and other monuments inspired by Egypt's great pyramids sprung up around the city, only two actual pyramids are known to have been built. The only one left standing, the Pyramid of Cestius, was designed as the burial pyramid for a Roman politician named Caius Cestius, who ordered that the building work be completed within a period of 330 days.
B Construction took place at some point between 18 B.C. and 12 B.C. Cestius' pyramid had a layer of white Carrara marble on the outside, and was constructed from brick held together by a basic kind of cement on the inside. One of the things that strikes you when you look at the pyramid is how steep it is, so that the shape of Cestius' pyramid is quite unlike that of typical Egyptian ones. This is a difference that could have been the result of inaccurate information sent back to Rome by soldiers who saw the pyramids in person in Egypt. Alternatively, Roman builders could have drawn inspiration from the pyramids in Nubia, a region located in what is today northern Sudan and southern Egypt.
C At the time of its construction, since there was a strict Roman law prohibiting the placement of tombs within the city itself, the Pyramid of Cestius would have stood in countryside. Rome grew enormously during the next two centuries, and, by the 3rd century A.D., the pyramid would have been surrounded by buildings. We also know that in the 3rd century A.D., the Pyramid of Cestius was hidden behind a high wall on the orders of Emperor Aurelian; this probably helped it survive throughout the centuries to come, even as other ancient monuments disappeared.
D By the Middle Ages, the pyramid was covered in vegetation and thick dirt, and popular myth had developed that it might be a tomb for one of the twin brothers Romulus and Remus, who were regarded as the men who had established the city of Rome. Cestius' actual tomb within the pyramid and the inscription identifying the pyramid as his weren't rediscovered until the 1660s when the pyramid underwent restoration. During excavations, when trees and plants were cleared away, two marble bases were found in front of the pyramid, as well as fragments of bronze statues that had once stood on them on either side of the pyramid. The people employed to excavate the pyramid did not find the urn that would have contained Cestius' remains, but they did come across a tunnel. It was quite possible, therefore, that robbers had at some earlier time removed the contents of the tomb. But while some of the features of Cestius' tomb no longer exist, at least the pyramid itself has survived.
E Today, the foundations of Cestius' pyramid rest below street level near an intersection with heavy traffic, so that passing tourists and residents could easily fail to notice its full height of 119 feet. Across the intersection is the Piramide station, located on Line B of the Rome Metro. In 2011, the Japanese clothing company entrepreneur Yuzo Yagi, president of Yagi Tsusho Ltd, announced his intention to help the Italian government pay for an ambitious renovation of the Pyramid of Cestius. 'It's an act of gratitude,' he later told journalists. 'Our company has grown thanks to Italy.' Work began at the site shortly after Yagi signed an official agreement with the Special Superintendency for the Archaeological Heritage of Rome, and was completed ahead of schedule thanks to his 2-million-euro contribution.
F As archaeologist Leonardo Guarnieri explained to journalists, officials are now conducting tours of the newly renovated pyramid twice a month by reservation. Visitors who take advantage of the tour can make their way through a narrow corridor in order to enter the burial chamber itself. It is within these walls that they can admire the frescoes: watercolour paintings typical of the time. In the chamber, it is possible to make out four frescoes of the winged Roman goddess of war, Victoria, a figure from Roman legend, as well as a series of vases, the type that would have been used for special rituals and purification purposes. We know from the writings of earlier visitors that there used to be more here, but the majority have disappeared over time.
G Only one problem remains now that the restoration is complete. The white exterior of the Pyramid of Cestius will have to be cleaned every few months to remove the layer of urban pollution. A team of free-climbers will be employed to do the job, in order to avoid placing builder's scaffolding around the newly welcoming monument.
Should we stop eating meat?
Some claim that it's the only way to save our planet from disaster. But is it really that simple?
A A call for people to eat less meat to save the planet is growing louder, so if less is good, wouldn't none be better? To find out, let's imagine what would happen if the world eliminated meat, milk and eggs from its diet, then trace the effects. Last year the world consumed 289 million tonnes of meat, 700 million tonnes of milk and 1.2 billion eggs. Environmentally speaking, this came at an enormous cost.
B All agriculture damages the environment. Take for example the felled forests and the common use of irrigation systems. And it may surprise you to know that agriculture creates more greenhouse gases than all methods of transport put together. Livestock farming does the most damage. In part, that is because most livestock eat grain that could be used to feed human populations, and farmers are forced to grow more than we would otherwise need to meet the demand. Altogether, if we switched to a vegan diet, meaning no meat, dairy or eggs, the land currently required for crops would drop by an estimated 21 per cent, about 3.4 million hectares, roughly the size of India.
C One environmental impact that would also lessen through a reduction in animal farming would be that of the nitrogen emitted from agricultural processes, which spreads into both waterways and land. According to environmental scientist Allison Leach, if everyone eliminated dairy products and eggs, this kind of pollution would fall by 60%. Livestock production has another serious environmental impact. Global statistics are hard to come by, but in the US at least, livestock account for 55% of erosion, mostly from forests being cut down to make way for grazing land. On top of this, half of all antibiotics manufactured are fed to livestock as part of their normal diet, a practice that is leading to drug-resistant bacteria.
D A meat-free world, then, would be greener in many ways. However, if everyone opted to give up meat there would be significant costs too. For most of human history, livestock grazed on land that wasn't suitable for ploughing, and in doing so they converted inedible grass into edible meat and milk. Even today, a flock of sheep or goats can be the most efficient way to get food from marginal land. In a world in which over a billion people do not have enough to eat, using this land for crop production would contribute to food insecurity.
E In some parts of the world today, livestock like chickens, for instance, can subsist on leftovers and whatever they find. Tara Garnett, who heads the Food Climate Research Network at the University of Surrey, points out the usefulness of these animals. By giving them your leftovers, she says, they deal with your rubbish, and you get meat. Garnett admits, though, that if this kind of approach were generally adopted, it would require a major adjustment in food preferences; people would have to get used to chicken, for example, with less fat.
F Another downside to a meat-free world would be the disappearance of animal by-products. Such a world would have to replace the 11 million tonnes of leather and 2 million tonnes of wool that come annually from livestock farming and which are turned into clothing. Furthermore, even ardent vegetarians acknowledge that dairy products and meat may be a good thing in poorer countries. 'Whilst there's no doubt that considerable reduction of meat consumption would have an environmental benefit, we do have to be careful about saying it would be the best solution if the whole world went vegetarian,' says Annette Pinner, chief executive of the UK Vegetarian Society. For many of the world's poorest rural residents, an animal may represent their only realistic hope for a little extra income, and a little animal protein can make a big difference to a marginal diet.
G What if we decided on a no-meat vegetarian diet, rather than a vegan diet? After all, milk and eggs are very efficient ways of producing animal calories. 'It's difficult to switch to no-meat but milk diet,' says Helmut Haberl, a social ecologist. 'Dairy cows must calve every year to keep producing milk, and only half their offspring will be female. While many vegetarians see moral reasons not to kill and eat the males, there is surely no practical reason to waste so much meat.' Similar arguments apply to chickens kept for eggs.
H So even though a meat-free world sounds good on paper, it is likely that a utopian future will still have some animal products in it. The real questions, then, are how much meat do we want, and how will we produce it? The answers depend on how you approach these questions. The most straightforward approach is to assume that the world will continue to want evermore meat. The United Nations' best guess is that by 2050, the world will need to more than double its production of meat, an increase that would be environmentally disastrous.
I Under this scenario the goal will have to be producing the most meat at the lowest environmental cost. According to Walter Falcon, an agricultural economist, this means fewer free-range cattle and sheep in green fields. 'If you're going to keep some livestock systems, I think the ones you'll want to keep are the intensive ones,' he says. Of course this does not take into account animal welfare issues, as intensive farming usually means poor living conditions and the use of growth hormones.
Travelling Plants
Plants need to produce more individuals of their own kind, and grow best away from their parent. So plants need to travel, and they do so in a variety of ways.
In an English woodland, the blackberry puts out exploratory stems, which curve upwards, waving slowly as though searching. If they touch another plant, they begin to advance directly and purposefully. To us, their motion is invisible, but for a plant it's an extraordinary rate – around five centimetres a day. When a stem makes contact with the ground, it puts down small rootlets, and starts to extract nutriment.
The silverweed is equally effective, putting out travelling stems that advance horizontally, creeping at low level through the mat of rootlets and dead vegetation formed by other plants.
In meadows, fescue grass is notable for annexing land from other less robust and aggressive species. The genetic fingerprints of its leaves and stems taken two hundred metres apart have proved, in some instances, to be identical. This must mean that one particularly vigorous plant has increased its territory year after year until now, after perhaps a century, it has become the largest plant in the entire meadow.
The bird-cage plant grows among sand dunes, in the deserts of the American west, and puts down long roots to search for water. But if the sand blows away, the plant's roots may shrivel up, the plant dies, and the stems form a hollow sphere. With no roots to anchor it, the wind blows it across the sand for several kilometres. Eventually it rolls into a sheltered site, allowing the seeds inside to germinate.
A few plants don't need external assistance to distribute their seeds. The Mediterranean squirting cucumber fills with a slimy juice as it ripens. Eventually the juice shifts so violently that the cucumber bursts off its stalk and shoots five or six metres through the air, leaving a trail of slime and seeds behind it.
One of the most dramatic detonating seed-containers belongs to a Brazilian tree known as monkey's dinner-bell. The side of the seed pod facing the sun dries out, causing an explosion which can hurl the seeds over twelve metres. The bang is enough to convince nervous strangers in the forest that they're under attack.
It's particularly important for trees that their seeds move far enough away to gain adequate light and nutriment. This is helped by the height of the tree, and in some cases by fitting their seeds with wings. Sycamore seeds, for instance, have a single wing, sprouting from one side. This makes the seed spin, and even in a light breeze, these tiny spinning helicopters can land far from their parent.
Instead of using wind or water as carriers, many plants use animals. The South African grapple plant, a low-growing creeper, relies on its seeds being trodden on. Its seed capsules have arms ending in hooks that are so sharp and strong, and point in so many directions, that when the foot of an elephant or rhino descends on one, the capsule becomes attached, and is carried by the animal.
Other plants reward their carriers instead of hurting them. Many plants that grow in the heathland of South Africa provide their seeds with an edible covering which ants find particularly attractive. These collect the seeds and carry them down to their underground nests, where they eat the covering, leaving the seeds themselves in an ideal position to germinate. Fruit seeds are completely enclosed with such a generous edible reward that the animal-carrier is encouraged to swallow both together. While the plant is constructing the seeds, the flesh of the unripe fruit is sour, and animals learn not to eat it.
But once the seeds are fully developed, the sap becomes sweet, and the fruit signals the fact that the seeds are now ready for transport by changing colour. Animals understand the signals well. They now eat the fruit, and carry the seed away inside their stomachs, to be ejected at a distance. Not all seeds have to pass through the entire digestive tract to be transported, though. The quetzal, a Central American bird, feeds on the wild avocado, swallowing it whole. It eventually regurgitates the stone, which then has a chance to take root and produce a new plant. Passage through an animal's gut is essential for some seeds, however. When the acacia of East Africa produces its seed-bearing pods, beetles fly in, lay eggs, and as the grubs hatch, they feed on the acacia seeds. The seeds can only grow if an elephant, or other animal, eats the pod, as its digestive juices kill the eggs. Eventually the seeds return to the outside world in the animal's droppings, and can germinate.
While the seeds of pine trees are developing, they're protected inside cones. When the seeds are ripe, one bird, the nut-cracker, is particularly skilful at picking them out. Those it can't eat immediately it buries, providing the seed with ideal growing conditions. But two out of every three seeds that the bird buries, it never finds again, so the tree uses a strategy of sacrificing a few of its seeds and relying on the poor memory of the courier who takes and conceals them.
So in one way or another, many seeds reach destinations where they can start their lives away from the environmental dominance of their parents.