u/ConspiracyUniversity

In 1995, engineer Chris Dunn examined ancient Egyptian core drill holes at Giza and measured the spiral grooves left inside. The tool cut through solid granite at a feed rate of 0.1mm per revolution, roughly 500 times faster than what modern diamond-tipped drills achieve on the same material without massive downward force.

The holes are perfectly cylindrical. The grooves are evenly spaced. And the drill cut through quartz and feldspar at the same rate, which shouldn't be possible with abrasive-based methods since those minerals have very different hardness levels.

Mainstream explanation is copper tubes with sand abrasive, but Denys Stocks' replication experiments produced irregular holes with uneven surfaces, nothing close to what's found at Giza. Petrie noted the same anomaly back in 1883.

Short video covering the evidence: https://youtu.be/gBcaNsAkY9U