Harvard Bridge

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Boston's Harvard Bridge crosses the Charles River between the Back Bay neighborhood and the MIT (not Harvard) campus. It's not really that photogenic of a bridge, and I only ended up with a handful of photos of it. I became distracted by other more interesting things and neglected to take any photos of it from the side until I was pretty far away. You can probably find better ones on the net somewhere if you're curious.

(Also, @Mile73 points out this is usually called the "Mass Ave Bridge", due to carrying Massachusetts Avenue over the river. That seems much better than naming it after a university it doesn't even go to.)

In the top photo, you might notice a green painted mark on the sidewalk, and (if you look closely) similar marks in various colors further away. These are "Smoot marks". Their story, as told by Wikipedia:

The Harvard Bridge is measured, locally, in smoots.

In 1958, members of the Lambda Chi Alpha fraternity at MIT measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot (who later became president of the International Organization for Standardization), end over end.

Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoots long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.

During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot-length slabs rather than the standard six feet. The Cambridge police use the smoot marks as a coordinate system when reporting accidents on the bridge.

Given that Smoot was 5 feet 7 inches (1.702 m) tall in 1958, the given measurement in smoots of 364.4 yields a "bridge length" of about 620 meters (2,030 ft). Published sources give the length of the bridge as approximately 660 meters (2,170 ft). The difference in length between the sidewalk markings and the published figure represents a 40-meter (130 ft) discrepancy.

An article at the Cambridge Historical Society mentions the Smoot connection, and points out a plaque marking the spot where, in 1908, a shackled Harry Houdini jumped off the bridge and made one of his famous underwater escapes. That's way cooler than any fraternity prank, if you ask me.