Tunneling is not a new or even recent human endeavour. Jews have been tunneling their way in and around Palestine for more than two millennia, such as the famous Siloah (SLX) Tunnel in east Jerusalem but which is not mentioned in the Hebrew Bible, so much so that Hamas has probably rediscovered, used and even expanded upon some of these ancient tunnel networks.
It makes perfect sense for Palestineans to create underground spaces in order to protect their persons and property from unwelcome Jewish invasions and attacks, especially from above.
