For the most part, Boston's history is best viewed when looking around or up. But sometimes, it pays to look down: Places such as downtown, the North End and Chinatown are filled with remnants of our commercial past, in the form of manhole covers. Read more.

Apparently a manhole outside 505 Boylston St., just past Clarendon, has been steaming all week, giving passersby a strong whiff of something awful. But today, it started steaming even more than usual, and firefighters, at first thinking they were dealing with a flaming manhole, doused the thing with liberal amounts of water. They summoned NStar, whose hole it is, to the scene; before an electrical crew could arrive, firefighters discovered the smoke was, in fact, steam.

Channel 4 reports fires erupted from manholes this morning when an NStar cable failed a bit catastrophically.

Boston Police report emergency crews first responded to an exploding-manhole report at 5:38 a.m. at Stuart and Tremont streets.

Flaming manhole this morning.

The Crimson reports on flaming manholes early this morning:

A fire started underground on the corner of Mass Ave and Dunster Street was visible through several manholes in the Square this morning. Harvard's Holyoke Center, Cambridge Savings Bank, Au Bon Pain, and other nearby institutions were evacuated, and automobile access to the Square had been severely restricted by the Cambridge Fire Department. ...

NeutralSurface took photos, including the one on the right.

Channel 5 reports. NECN has video on "the underground mechanical failure" as well (great fire-AND-ice NECN screen capture).

Sushiesque was on the scene later in the morning taking photos of the aftermath:

Mishka gets the day off.

Michael: On second thought, maybe I'll go to Yale.

Crispyfoods captures Old Flameful outside the Pit:

Manhole explodes this afternoon on Needham Street near Rte. 9 in Newton (two blocks from Margalit, who is starting to wonder what the deal is with her neighborhood's karma).

Tires blown at coverless manhole on Nonantum Road in Brighton this morning.

Two more, in the same basic area on the Southeast Expressway as the one that got wedged in a bus yesterday; one driver lost control and slammed into a Jersey barrier.

Couple this with Josh Simons's HazMat game (identify hazardous cargos by the numbers on the placards on the back of the trucks) and you get a new way to spice up the commute: "Say, Bob, whadaya think would happen if a flying manhole cover sliced through that truck with the '3' hazardous placard?"