Descend into the oldest caves in the world! 340 million years old, the Jenolan Caves harbour a 40km network of caves comprising some 300 cavities. Ten of them are open to the public, including Lucas, the largest and most visited, Chifley, the first in the world to have benefited from electric lighting, and Jubilee, the longest (1 600m). On the whole the tours, led by chatty guides with plenty of information at their fingertips, are not physically demanding, save for the stairs you will need to climb.