One of those places that feels like another planet. Las Grietas are volcanic fissures carved into the slope of Montaña Blanca — three cracks in the rock where you can literally walk inside the volcano's layers. The walls around you are solidified lava from different eruptions, stacked like pages of geological history. We went into the main fissure without doing the full summit hike — and it was more than enough. Narrow, dramatic, completely silent inside. Bring water, wear closed shoes, and don't forget sunscreen for the approach — there's zero shade until you're in the crack.