 The original moat around the tower would have been a simple design , but it was redesigned in the 1460s to provide a walkway around the outside of the Great Tower . The niches in the walls of the walkway are of 17th @-@ century origin , and would originally have held classical statues - the walkway would have provided a dignified way of admiring the Great Tower . It is likely that fish would have been bred in the moat . 
