This is one of those blog posts which is about something really quite mundane but which might possibly be quite interesting in a decade or three. Maybe.
You’ve seen lots of these around. This is a fire hydrant. Or at least, it’s the cover of a hydrant. The bits that actually work are underneath it, and are quite low to the ground.
This is also a fire hydrant. I’m assuming it’s an older one, as everything is visible — it doesn’t have a cover. This might be what people think of in their minds when they think of what a fire hydrant looks like.
And have you noticed these? I remember being told about them as a kid, I think on an excursion to the (now defunct) Elwood fire station. A blue rectangle on a power pole means there’s a fire hydrant up ahead. A square means it’s back behind you. I’m guessing these make it easier for the fire brigade to find a hydrant (especially at night) when they need it.
Update 6/10/2013: Some mention in the comments of blue reflectors (“cats eyes”) on the road to additionally help locate hydrants. For completeness, here’s a photo of one.