Australians have built the underground town of "Coober Pedy" in northern South Australia to escape extreme heat. The area is famous for its opal mining. Some of the most spectacular opals in the world come from here.
The mesmerizing beauty of the Postojna Cave and the mysterious castle of Predjama rank among the most precious jewels of Slovenia. Discover the wonderful underground world of Postojna Cave and explore the striking medieval Predjama Castle.