On August 5, 2010, a block of diorite, hard rock the height of a skyscraper, tore loose in Chile's San José copper-gold mine.
It fell through the levels as if they were cardboard.
Thirty-three miners were trapped 2,300 feet (700 meters) underground, 3 miles (5 kilometers) from the entrance.
For 17 days there was no contact at all.
No one above ground knew if anyone below was still alive.
Then a drill bit came up with a note taped to it.
"Estamos bien en el Refugio los 33."
We are well in the refuge, the 33.
They waited on long benches while crews from several countries drilled a rescue shaft.
No one in recorded history had survived so long trapped underground.
How deep is 2,300 feet?
More than one and a half times the Empire State Building, only downward into the rock.
On October 13 they were pulled up one by one in a specially built capsule.
After the last man, rescuers still underground held a sign to the camera: "Misión cumplida Chile."
More than a billion people watched on television around the world.
They came out alive.
Not because the mountain gave way.
Because for 69 days someone kept digging.
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