Luddites used to wreck these towers (5)
I believe the answer is:
looms
I believe this clue is a double definition.
'luddites used to wreck these' is the first definition.
(19th-century Luddites destroyed looms)
'towers' is the second definition.
('loom' can be a synonym of 'tower')
(Other definitions for looms that I've seen before include "Rises threateningly ahead with weaving machines" , "More than one machine" , "appears indistinctly" .)