Huaca de la Luna

Start with the ground under your feet. It is dry, pale sand, the colour of weak coffee with milk. The air smells of dust and warm earth, and the light here on the north coast of Peru is flat and bright, almost white. Behind you rises a bare, rocky hill called Cerro Blanco. In front of you stands a mountain of mud bricks. It does not look like much from a distance. Then you step inside, and the walls turn red, yellow, white and black.

This is Huaca de la Luna, the Temple of the Moon. It sits a few kilometres outside Trujillo, in the valley of the Moche River. The word huaca comes from Quechua, a language of the Andes. It means a sacred place or a sacred object. The name "of the Moon" was given much later, long after the builders were gone. The people who made this temple never called it that. We do not know what they called it at all.

The builders were the Moche, a civilisation that flourished on this coast roughly from the first to the eighth century of our era. That is centuries before the Inca. The Moche had no writing system that we can read. Everything we know comes from what they left behind: their buildings, their tombs, and their remarkable pottery. Their ceramics show faces so lifelike that you could almost recognise the individual. They also show warriors, healers, animals, and gods in great detail.

Now look closely at the walls. The whole temple is made of adobe, which is sun-dried mud brick. There are millions of these bricks in the structure. Here is the first detail most visitors miss. Many bricks carry small marks pressed into the clay — lines, dots, simple shapes. Archaeologists believe these marks identify the groups who made them. Different communities may have paid a kind of labour tax in bricks, and each group signed its work.

The second surprise is how the temple grew. The Moche did not build it once. Over generations, they built a temple, used it, and then sealed it. They filled the old rooms with bricks and built a new, larger temple directly on top. This happened several times. The result is like a set of nesting boxes. As you walk through the excavated corridors, you are often looking down into an older temple, preserved because the newer one buried it.

That burial is the reason the colours survive. The painted reliefs were covered over and protected from sun, wind and rain for many centuries. When you look at the walls, you see them close to how the Moche saw them. Notice the repeating face set inside a grid of diamond shapes. It has wide eyes, a snarling mouth, and fangs. Waves or curling forms often surround it. The face appears again and again, in panel after panel.

Scholars often link this figure to a powerful Moche deity. You may hear the name Ai Apaec, sometimes translated as "the maker" or "the creator". Many people also call him the Decapitator, because Moche art shows a fanged figure holding a knife in one hand and a severed head in the other. Keep in mind that the exact identity of this god is still debated. The Moche left no text to tell us. What is clear is that this face mattered enormously to them.

That brings us to the darker side of the temple. Behind the main platform, archaeologists excavated a plaza containing the remains of dozens of men. Their bones show injuries consistent with combat and with ritual killing. Some remains were found in layers of mud, which suggests heavy rains fell during or soon after the ceremonies. On this desert coast, heavy rain usually comes with El Niño, the warming of the Pacific that can bring floods. Researchers think these sacrifices may have been an attempt to restore order when the climate turned violent.

Now walk around to the great north facade. This is the image that stays with most people. The wall rises in tiered bands, like the shelves of a giant bookcase. Each band carries a different scene. On one level, a line of warriors leads naked prisoners by ropes. On another, figures hold hands in a long chain, as if dancing. Higher up you see spiders, sea creatures, and the fanged face again. The colours are bold and clean, especially the red and the yellow.

Stand back from the facade for a moment. Imagine it complete and freshly painted, facing a large open plaza full of people. This wall was designed to be seen from a distance by a crowd. The procession of prisoners was not a private image. It was a public message about war, power and the gods. Even today, without understanding a word of the Moche language, the message is easy to read.

Now turn and look across the plain. The large, eroded mound in the distance is Huaca del Sol, the Temple of the Sun. It was once one of the largest adobe structures in the Americas. Much of it is gone. In the colonial period, Spanish treasure hunters diverted the Moche River against its side to wash away the bricks and search for gold. The cut-away shape you see is the scar of that destruction. Huaca del Sol is generally not open for visitors to walk on.

Between the two temples lies the open ground that once held a Moche town. Excavations here found houses, workshops, streets and storage rooms. This was not only a ceremonial centre. People lived here, cooked here, made pottery and wove cloth here. Archaeologists from Peru have worked at this complex for decades, and the digging continues. On some visits you may see excavation areas covered by shades or roofs. Those roofs protect fragile painted walls from sun and from the rare but serious rain.

You may also meet a local resident with no hair at all. Peruvian hairless dogs often wander the archaeological sites of this coast. They are an old breed, and they appear in Moche art, too. Before you leave, the site museum nearby is worth your time. It holds ceramics and objects found here, including pieces that help make sense of the walls you just saw.

So take one last look around. The hill of Cerro Blanco stands behind the temple, just as it did for the Moche, and many researchers think the hill itself was sacred to them. The painted faces stare out from the walls. The sand shifts under your shoes. As you walk back toward the entrance, look at the plain mud bricks in the outer walls. Somewhere in them, a small mark pressed by an unknown hand is still waiting to be noticed.