A giant art display of 69 red bicycle wheels has mysteriously disappeared from a street in Bath.
The huge textile display took two vans to install on George Street and was created to draw attention to the level of air pollution in the city.
Police are investigating the suspected theft but currently have no lines of enquiry.
The eye catching exhibition had been in place less than two weeks before it was noticed missing on 4 October. Creator Alison Harper says she is "immobilised" by the news of its theft.
Ms Harper, who has been living in Batheaston for 35 years, collected the 69 bicycle wheels.
She coloured them red and embellished them with cloth and yarn before installing the artwork with the help of 18 members of Transition Larkhall - a community group.
Joanna Wright, now Cabinet Member for Transport Services, commissioned the piece before she was elected. Ms Wright says she wanted an artwork which would visually represent the issue of air pollution in Bath:
"I was very shocked to hear that they had been stolen. Obviously people just don't want to know that air pollution kills people.
"It's three months of hard work gone, there was such a huge effort behind the art work."
The location of the display, George Street, is one of the city's hot spots for high levels of air pollution, specifically nitrogen dioxide created from vehicle exhausts.
Artist Alison Harper is determined to turn the theft into a positive.
A spokesperson for Avon and Somerset Police said:
"A sculpture with a message for pollution - 69 bicycle wheels tied with red string - has been taken from the corner of George Street and Gay Street.
"This happened between October 2 and October 4.
"There are no further lines of enquiry and the matter has been filed, pending any new information."
Anyone who has information is asked to contact police.