My company recently moved to another location in Arlington Ma (on the Cambridge/Somerville line). One of my co-workers is also a history aficionado & asked me to come with him & check out what he thought was a WWII era air raid siren on top of a telephone pole next to our bldg. That's what it is alright. We found out that our bldg was owned by a telephone co in the 1920s & 30s.
I wonder how many of these are out there, but no one remembers what they were for.
http://articles.latimes.com/2007/apr/29/local/me-then29
http://en.wikipedia.org/wiki/Air_raid_siren
Great Post! I enjoyed reading the links.
I didn't know about the Los Angeles fiasco. My goodness, can you imagine the chaos and panic? Wow!
Here's to those old relics and the memories they stir up.
I was born in 1937 in the small seaside town of Deal on the south coast of the UK. We were just over 21 miles
from the French coast and the wail of air-raid sirens was a daily feature in my life from the age of two.
Colin. 
Hard for us Americans to realize all you Brits went through on a DAILY BASIS! And as you said, it was something you were brought up with. It WAS the NORM for you. Let's hope Great Britain nor any of us, has to experience anything of that magnitude ever again.