Have you noticed any of those red, square-shaped "U" signs that have been appearing above the entrances of buildings around town? Wondered what they could mean? Me too.

I first saw one a few months ago, above the side entrance of Union Jacks club on East Burnside Street, and then another outside the Kingston pub on West Burnside.

The signs indicate a building that Portland Fire & Rescue has deemed "unsafe." From a PF&R memo from December: "The Unsafe Buildings Alert Program provides a tool for identifying structures that, due to their construction, use, or state of maintenance, pose extraordinary hazards to emergency personnel."

There are currently signs on a couple dozen buildings around town. If one of the buildings catches on fire, PF&R crews will attempt to fight the fire from outside rather than enter the building. They will go inside if they need to perform a rescue, for example, but will keep their time inside the "unsafe" structure as short as possible.

Any of these dilapidated death-traps in your neck of the woods?