Zia Ul Haq, Indian PM and US President were discussing ancient civilization. Zia Ul Haq mentioned: Our civilization was highly advanced. When we dug 2000 ft underground, we found copper wires, indicating we had telephone lines over 1000 years ago.
The Indian PM, not to be outdone, responded: That is nothing - when we dug 4000 ft underground, we found nothing. That showed we had wireless communication 2000 years ago!