An Example Is "what Has an Eye but Cannot See"

This page is the CodyCross answer for the clue below from Trip to Spain, Group 849, Puzzle 3 (Real Madrid).

Question is: An Example Is "what Has an Eye but Cannot See"

and the answer is: RIDDLE

Word Meaning:

RIDDLE — A verbal puzzle, mystery, or other problem of an intellectual nature.

Definitions from Wiktionary.