Crossing the High Atlas mountains of Morocco you may come upon a village impossibly remote, set high on the edge of a gorge. After a sti ff climb you reach it, thinking that it must be the very last village.
But no, there's a track leading upwards, and as you round a bend in the gorge, you see another village seeming to rise from the Earth itself, but way, way above you. So you head for this village, thinking there can't possibly be another... and yet there is, and another and yet another still, until you give up, realising you'll never reach the very highest village.