Pyramids of Güímar

Listen first. Under your shoes, loose volcanic gravel shifts and crunches. The air smells of dry earth and warm stone. Somewhere a bird calls from a palm, and beyond it, faintly, a car climbs the road out of town. In front of you are terraces of dark, rough rock, stacked in steps and edged with surprisingly sharp corners. These are the Pyramids of Güímar, and they are one of the most argued-about piles of stone in the Canary Islands.

You are standing in the Chacona area of Güímar, a town on the southeast coast of Tenerife. The valley slopes down toward the Atlantic, and on clear days the ocean shows as a pale line below. Behind you, the land rises toward the high centre of the island. It is a farming valley, and that detail matters. Keep it in mind as we walk, because the farming story and the pyramid story turn out to be closely tied.

Look closely at the walls. There is no mortar here. Each block is a piece of basalt or lava stone, fitted against its neighbours by hand. Some stones are fist-sized. Others would need two strong people to lift. The builders chose flatter faces for the outer edge and packed smaller rubble behind them. The result is a stepped platform, with a flat top and, on several of the structures, a stairway leading up one side.

Six of these stepped structures stand in the park today. They are not tall like the pyramids of Egypt. They are low and broad, more like layered terraces than pointed monuments. Even so, when the light comes in low across them, the shadows line up in neat bands, and the shapes look deliberate. That impression of deliberate design is exactly what pulled one very famous explorer to this valley.

That explorer was Thor Heyerdahl, the Norwegian adventurer best known for the Kon-Tiki expedition, when he sailed a balsa-wood raft across the Pacific in 1947. Heyerdahl spent his career arguing that ancient peoples crossed oceans far earlier than most scholars accepted. In the early 1990s he came to Güímar, studied these stepped platforms, and began to wonder whether they could be linked to the stepped pyramids of Mexico, Peru and Mesopotamia.

Here is the first surprise. Heyerdahl did not only study the pyramids — he settled nearby and spent his later years on Tenerife. With the backing of the Norwegian shipping businessman Fred Olsen, he helped turn this site into the ethnographic park you are walking through now. So this place is two things at once. It is an archaeological site, and it is also a kind of memorial to one man's bold, and much debated, ideas.

Now for the other side of the story. Archaeologists from the University of La Laguna excavated here in the early 1990s. Their conclusion was much plainer than Heyerdahl's theory. The evidence they found pointed to construction in fairly recent centuries, most likely around the nineteenth century. In their reading, these were not temples at all, but the work of local farmers.

Why would farmers build stepped platforms? Look at the ground around you. Tenerife's soil is full of volcanic stone. Before a field could be planted, it had to be cleared, and the cleared rock had to go somewhere. Across the Canary Islands, farmers stacked it into walls, terraces and heaps. Seen this way, the pyramids are the tidy leftovers of hard agricultural work, built with real care and skill.

But the debate did not end there, and this is the second surprise. Astronomers looked at how the structures are oriented. They noted that some of them appear aligned with the sun at the solstices — the longest and shortest days of the year. Locals and visitors often describe a summer solstice evening when the sun seems to set behind a mountain ridge, briefly reappear, and then set again. Whether that alignment was planned, or is simply a coincidence of landscape, is still discussed.

There is one more layer beneath your feet. Long before the Spanish arrived in the fifteenth century, Tenerife was home to the Guanches, the island's indigenous people, who lived in caves and herded goats across these slopes. Excavations here found traces of older activity in a cave close to the platforms. So even if the stone steps are relatively young, people were using this patch of land long before anyone stacked a single terrace.

As you continue through the park, you will find more than stone. There are exhibits about Heyerdahl's voyages and his theories, with models of the reed and raft boats he used to test his ideas at sea. There are also planted gardens with plants from the Canary Islands, including a section of poisonous species. Read the labels before you touch anything — some of the most attractive leaves are the ones to leave alone.

So what are you really looking at? Perhaps a farmer's solution to a stony field. Perhaps something that carried a meaning we no longer fully understand. Perhaps both. The honest answer is that the evidence leans toward the farming story, while the solstice question keeps the conversation alive. And Heyerdahl's bigger idea, that ancient sailors may have crossed the Atlantic, is still a theory most scholars do not accept.

Before you leave, stand still for a moment beside the nearest platform. Put a hand on the stone if it is not too hot. Feel how rough it is, and how each block sits against the next without any glue at all. Then look past the terraces to the line of the ocean, and up to the ridges behind the town. Whoever stacked these stones looked at this same view, with the same sun moving across the same valley.