the inside of a cave with a doorway

The Mysterious Altar Right below the portal door, we can see the rough remains of what looks like a missing foundation that was apparently destroyed. On the right side of the cave, we can see the remains of another precise carving, with the carving continuing on the other side of this piece of rock. It appears a massive catastrophic event destroyed this site, dispersing all of the missing rock pieces. Who knows what the true scale of the site truly looked like thousands of years ago? Facing right at the entrance of the cave, there's the most remarkable structure of Nyapahuaca, the so-called altar. This mind-blowing megalith was carved from bluestone, and this is the only outcrop of bluestone found in the entire region. Bluestone, standing out in stark contrast against the surrounding sandstone, contains a type of crystal prized for its exceptional piezoelectric properties. For this reason, bluestone was once used in early radio receivers.