Plato's Allegory of the Cave is a philosophical metaphor found in his work, The Republic. It describes prisoners who have been chained inside a dark cave their entire lives, only able to see shadows cast on a wall by objects behind them. These shadows represent their limited perception of reality, as they believe the shadows are the only truth. One prisoner eventually escapes the cave and discovers the outside world, realizing that the sun represents the ultimate truth and knowledge. This journey symbolizes the philosopher's quest for enlightenment and understanding, contrasting the ignorance of those still trapped in the cave.