The Undara lava tubes can only be visited by guided tour and there are three main daily tours leaving from the Undara Experience Resort, including the two-hour Archway Explorer and Active Explorer. A highlight is Wildlife at Sunset (adult/child $60/30) where you'll see tiny microbats swarm out of a cave entrance and provide dinner for lightning-fast hanging tree snakes known as night tigers. Nature at its best!
Tours, led by experienced Savannah guides, require some walking but mostly on boardwalks. Book at least a day in advance.