From the top of Mission Hill yesterday:
Oh, and I love finding relics like this...
Originally I thought these led to the Parker Hill Reservoir that was here from the 1870s(?) to the early 1900s, but on second thought I believe they were constructed in the 1910s when Robert Breck Brigham built his hospital up here. This is from 1929, and you can see the stairs leading to the building up top:
BPL on Flickr
The buildings in the middle are still there and are now part of New England Baptist (which at the time was in the smaller buildings in the bottom of the pic) but the upper structures were gone by 1938, so those stairs would've only been in use for a couple decades before being orphaned.
And before the hospitals was the reservoir, though I haven't been able to find any actual pictures of it.
OK there's your history lesson for the day.