On the island of Gran Canaria, a team of archaeologists has discovered a hidden subterranean chamber lined with polished obsidian plates. The chamber, built by the indigenous Guanche people around 1,000 CE, features a roof aperture that allows a single beam of light to strike a central altar only during the summer solstice. This site is believed to be the primary location for the 'Festival of the Great Sun,' a ceremony described in early Spanish chronicles but never physically located until now.
The obsidian plates were used to reflect the sun's light throughout the dark chamber, creating a shimmering 'celestial' effect during the height of the ritual. Excavations around the chamber have also yielded remnants of barley and goat milk offerings, which were central to the Guanche's agricultural New Year. This finding provides critical archaeological weight to the heritage of the Canary Islands and the sophisticated astronomical knowledge of its first inhabitants.