00:00Water pressure should crush tunnels, right?
00:02Think again.
00:04Underwater, massive water weight squeezes the tunnel walls inward.
00:08This pressure seals tiny cracks.
00:11Earth itself hugs the tunnel tight.
00:14Deeper it goes, stronger that hug gets.
00:18Engineers use special rings.
00:20Water pressure pushes them tight.
00:22It creates a self-sealing bond.
00:25Water pressure makes these tunnels stronger.
00:27For more wild secrets, check the link in bio.
