Ometepe is one of the richest petroglyph sites in Central America, with carved boulders scattered across the slopes of Maderas — many still sitting in active fields and pastures. The carvings are mostly pre-Columbian, attributed to the Chorotega and Nicarao peoples who occupied the island before Spanish contact. Spirals, monkeys, frogs, snakes, and crowned human figures all appear.
The easiest way to see them is on a guided walk from one of the lodges around Balgüe or Mérida; Finca Magdalena, an organic coffee cooperative on the Maderas side, has a particularly good concentration of stones on its land. The Ceibo Museum in San José del Sur also has a small but well-curated collection of artefacts and replicas.