A bandstand at the Venetian Waterways in Great Yarmouth has been vandalised.
Three of the shelter's surrounding low brick walls were knocked down into the public footpath, with supporting wooden beams and uprights also damaged.
Norfolk Police said the incident happened sometime between Sunday (March 28) and Monday (March 29).
The bandstand has since been cordoned off, pending repairs, while enquiries are ongoing.
The Waterways were reopened in April 2019 after a £2.7m restoration.
Penny Carpenter, chairman of the environment committee at Great Yarmouth Borough Council, said: "That someone would do mindless damage to a much-loved and unique part of our community heritage, especially so soon after the park’s award-winning restoration by dedicated volunteers and the council, is extremely disappointing and shows total lack of respect.
"We’re appealing to the community and to good public spirit to help identify the offenders so the police can take action."
Witnesses or those with information can contact Norfolk Police on 101 or Crimestoppers on 0800 555 111, quoting crime reference number 36/20223/21.
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