One old fort now turned into a capital attraction (5,2,6)

I believe the answer is:

tower of london

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'a capital attraction' is the definition.
The definition suggests a singular noun which matches the answer.

'one old fort now turned' is the wordplay.
'turned' indicates anagramming the letters.
'one'+'old'+'fort'+'now'='oneoldfortnow'
'oneoldfortnow' is an anagram of 'TOWER OF LONDON'.

'into' acts as a link.

Can you help me to learn more?

(Other definitions for tower of london that I've seen before include "Home to the UK's Crown jewels" , "C eleven capital fortress" , "Fortress on the Thames" , "Where the Crown Jewels are kept" , "Where to see crown jewels" .)

I've seen this clue in The Globe and Mail.

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