The massive boulders at Ayo and Casibari are a mystery, as they don't match the island's geological makeup. You can climb to the top for fine views of the arid countryside. On the way you'll doubtless pass Aruba whiptail lizards—the males are cobalt blue, and the females are blue-gray with light-blue dots. The main path to Casibari has steps and handrails the entire way (except on one side), and you must move through tunnels and along narrow steps and ledges to reach the top. At Ayo you can find ancient pictographs in a small cave (the entrance has iron bars to protect the drawings from vandalism). You may also encounter boulder climbers, who are increasingly drawn to Ayo's smooth surfaces. Access to Casibari is via Tanki Highway 4A; you can reach Ayo via Route 6A. Watch carefully for the turnoff signs near the center of the island on the way to the windward side.
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