It was the first thing they saw when the sun rose. It was the last thing they saw when they left. Their forebears had built it, an impregnable structure with a message it seemed only they could decipher.
For millennia, humanity had broken against this cliff, scratched and scraped at the smooth material of the obelisk, pored and scratched their heads over its inscriptions. Now they were gone; it was too late to save them. They had come so close to enlightenment, but wave after wave of senseless violence and hatred had consumed the feeble flicker.
With one last, sorrowful look back at the beacon of hope as it glittered in the evening light, they left it to the waves and the sunset and continued their journey to visit the other beacons scattered throughout the universe.