Lighter Than Air But Connot Move Me Riddle

Riddle: I am large as a castle, yet lighter than air. 100 men and their horses cannot move me. What am I?

Answer: The castle's shadow.

Source: https://www.riddles.com/213

Riddle: I am large as a castle, yet lighter than air. 100 men and their horses cannot move me. What am I? Answer: The castle's shadow. — by Anonymous v1.

Riddle: I am large as a castle, yet lighter than air. 100 men and their horses cannot move me. What am I? Answer: The castle's shadow. — by Anonymous v2.