Birds perched on an illuminated advertising sign

In the Finnish city of Kajaani, the roof of the Kauppapaikka 18 shopping center collapsed two months ago. The cause of the crash was pigeon droppings, Yle TV channel reports.
The roof structure fell right onto the street in front of the main entrance to the shopping center. According to an engineering company investigation, the crash occurred as a result of overstressing an illuminated sign.
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Because of the warmth, the illuminated sign was especially attractive to the pigeons. Birds often sat in this place and left droppings. At some point, one of the structures ceased to withstand pigeon droppings, the load was transferred to the neighboring one. The resulting chain reaction led to the crash.