Santa Cruz Island is composed of two parts: a younger and larger portion is formed by many volcanic cones and basaltic lavas, while the older part is a narrow, 10-mile strip of land along the northeastern coast and consists of uplifted submarine lava flows and tuffs.

Santa Cruz Island is the second-largest island in the Galapagos and something of a hub for the archipelago. Puerto Ayora, located in the southeast of this large, round volcanic island, is the economic center of the Islands.

Puerto Ayora is home to both the Galapagos National Park Service Headquarters and Charles Darwin Research Station, the center of the great restorative efforts taking place in the park, a UNESCO World Heritage site.  

A highlight of any trip is a visit to Santa Cruz Highlands, where the dry coastal vegetation transitions to lush wet fields and forests overgrown with mosses and lichens. Our destination is the Tortoise Reserve, where we will have chances to track and view these friendly and ancient creatures in their natural settings. This extends to the adjacent pasturelands, where farmers make some profits by allowing visitors into their farms in exchange for payment. The best time to see tortoises here is during the cold or dry season from June through December. Another nearby attraction is the highland lava tunnels. Some of them offer easy access through wooden stairways that descend to the mouth of their arched cave entrances. From there, one can make their way into the caves underground along the cool, dimly lit naturally formed passages with their fascinating rock formations. The tunnels make for a relatively easy and exciting hike. You should bring along non-slip footwear and some hikers prefer to use a flashlight.