Cuicuilco

Cuicuilco is an archaeological site in the Tlalpan district of Mexico City, where a large circular pyramid built from stepped stone terraces forms the central structure. The pyramid stands in a broad plain, partly surrounded by hardened lava that once flowed across the area and sealed certain zones.

The settlement emerged around the third millennium BCE and grew into an important center before a volcanic eruption buried it under lava in the first century CE. Its inhabitants left the area, and the ruins remained hidden for centuries until archaeologists began uncovering them in the early twentieth century.

The site was restored after its rediscovery, and archaeologists uncovered traces of offerings and ritual objects that remain visible in selected areas today. Visitors can see how this early society held ceremonies in the open air, directly on the pyramid terraces, where people gathered to observe the sky.

The site is mostly open and flat, allowing visitors to view the pyramid from different angles, while a small museum nearby displays finds from excavations. Most paths are easy to walk, and shade is sparse in some areas, so sun protection is advisable.

The pyramid's circular shape differs markedly from the rectangular structures of later Mesoamerican cultures, pointing to distinct building traditions. Parts of the original surface remain preserved beneath the lava layer, helping researchers reconstruct life before the disaster.