Fragment of a National Geographic show "Megastructures" where a new technology is presented to drill a hole into granite. It can drill a hole of 5" diameter, 10" deep in just 3 minutes..
[ Ссылка ]
![](https://i.ytimg.com/vi/JhXl8rrVzTU/mqdefault.jpg)
Fragment of a National Geographic show "Megastructures" where a new technology is presented to drill a hole into granite. It can drill a hole of 5" diameter, 10" deep in just 3 minutes..
[ Ссылка ]