For Becky’s ‘UP’ square, today, I’m featuring two views of the Undala lava tubes of Queensland; outside and inside the tubes.
The longest lava tubes in the world, they are formed (to give a lay explanation) when a huge mass of lava is on the move, but cooling as it runs. Subsequent lava flows add to it and run up the sides, eventually closing over the top to form a tube.
The last eruption was about 200 000 years ago.
Not so far from Cairns, they are well worth the visit.