The great French composer and theorist Olivier Messiaen (1908-1992) famously spoke of "the charm of impossibilities." When Messiaen used the phrase, he was usually referring to what he called "modes of limited transposition," or a distinct set of seven scales which, due to their inbuilt symmetry, can only undergo a limited number of transpositions before folding back into themselves. Each of the modes contains elements with which we're all familiar---the chromatic pitch-classes of the traditional Western equal-tempered scale---but arranges them in an order that transforms them, transmutates them into something new, something mysterious, something at once extraordinarily simple and yet remarkably complex. Suddenly these pitches we know so well are heard as sounds from another world. They lack the traditionally stabilizing element of a tonic or a key signature, but their adamantine structure makes them stable to the point of immovability.

The Hancock Tower (which is really called "Hancock Place," but I don't think anyone's called in that in a couple of decades) is both impossibly beautiful and impossibly impossible. It's atowering monolith that dwarfs everything in its immediate vicinity, but---if the conditions are just right---it's virtually invisible. It thrusts up from the earth with verticality and violence, and yet maintains a sense of weightlessness, of floating, of being some figment of a half-remembered dream.

The most charmingly impossible (and impossibly charming) aspects of this building, though, are a little harder to see. A decades-long engineering experiment, the Hancock is a testament to the power of will and intellect in the face of remarkably adverse conditions. In the 35 years since it was finished (and, really, the 43 years since plans were first drawn up), the Tower has been in constant war with the laws of physics, the laws of chemical engineering, and the laws of municipal government.

Here's a little overview, in something resembling chronological order.

1968: The general public reacted with vehemence when the Tower's location was announced. Its proximity to Henry Hobson Richardson's beloved Trinity Church was apparently sacrilegious, as it meant the church might occasionally be in the shade.
1968: Back Bay, being essentially swamp land, proved inhospitable to such a large structure from the very beginning. Excavating the foundation was especially disastrous, as the temporary steel retaining walls---erected to keep the mud in check---began to buckle and destroy all sorts of infrastructure in the greater-Copley area. Power cables, telephone lines, sidewalks, pavement, you name it. Even Trinity Church suffered some damage, which was, apparently, another act of sacrilege.
1971-73: The most infamous issue plaguing the building (though not the most hazardous (see below for that one)) was also the most visible. The problem was that the Hancock started losing windows. Gigantic, 500-lb. windows. Almost immediately after the curtain wall was completed, the panes started popping out with remarkable regularity. In an effort to keep the building vaguely weatherproof, the architectural firm (more on them to come) replaced the fallen windowpanes with plywood. It didn't look very good. Eventually, all 10,344 panes were replaced. Years later (and after much speculation), engineers pinpointed the root of the problem: the bonds holding the glass panes in place. The window structures were actually quite cutting-edge for the time: dual-paned, chromium-coated, insulating, you name it. The issue was that the lead-tape spacer (so tiny it'd be barely visible) was creating too firm a bond with the sheets of glass on either side of it. It was, in a sense, over-engineered. Because of numerous factors (thermal flux being perhaps chief among them), the spacer's tenacious grip meant that there was no wiggle room, which---though you'd think it'd be a good thing---made the bond completely inflexible. The spacer was actually stripping microscopic bits of glass from the panes, which ultimately weakened the bond and led to a very costly (not to mention hazardous) situation.

Photo: Michael Shellenbarger/ University of Oregon Library

1976: Tenants of the upper floors began calling out of work sick due to chronic nausea caused by the Tower's "cobra dance." The "dance" was caused by rather significant amounts of swaying and torsion, a problem only exacerbated by the unique structural properties of the building: the natural periods of vibration of the twisting and lateral bending motions were very close to one another, so neither cancelled the other out. One of the cooler engineering solutions I've ever heard of was then proposed and carried out: two colossal "Tuned Mass Dampers," a recent invention consisting of 300-ton lead and steel boxes floating on a nearly frictionless surface, attached to the core of the building by way of shock absorbers. When the building sways, the dampers stay more or less in place, counterbalancing the motion beautifully.
Shortly thereafter: The most dangerous problem, it turned out, was kept secret for years. After the PR disaster of the falling windows, the firm wasn't about to disclose what was one of the more shocking engineering dilemmas of the late-twentieth century. An engineering review found that under very specific (but not necessarily abnormal) wind conditions, the Tower was in acute danger of falling over on its narrow side. Yup, that's right, the narrow side. The effect this would have on the surrounding environment would be essentially that of a 790-foot guillotine. A 790-foot guillotine encased in glass. The firm immediately began efforts to fix the problem, and fortified the core of the building with 1,500 tons of steel bracing. Word eventually got out, but luckily the building was just about the safest on the planet by that point.

So why didn't they just give up? Why didn't they scrap the design and try something else, something simpler, something more proven?

I'm not sure exactly, but I think it's got something to do with the fact that the Hancock Tower is perhaps the most beautiful mid- to late-twentieth century building in Boston. Speaking personally, I can't think of a better skyscraper created anywhere in the 1970s. The Hancock is the singular fulfillment of everything the Modernists had sought to achieve for the better part of a century. It's outrageously clean---it's a building that outwardly appears to consist of little else but windows, and yet the curtain wall appears to be devoid of mullions (from far away, at least).

The firm responsible for the architectural design of the Hancock was I.M. Pei & Partners (you might've heard of 'em). The chief architect wasn't Pei, though he was involved. It was the remarkable (and remarkably undervalued, in my opinion) Henry Cobb, a man responsible for other Boston gems like the Harbor Towers and the Moakley Courthouse. The falling windows fiasco almost put an end to his budding career, but a series of critical and public successes helped put him back in high regard.

Mies van der Rohe's hugely influential Seagram Building---erected in New York about a decade before work started on the Hancock---represented what many thought to be the perfect embodiment of the International Style. It was, for many architectural buffs, the ideal manifestation of form following function, and it sounded a clarion call for similar office structures to be erected around the country. A flood of dark, glass pylons began appearing in major cities around the country (see, for example, one of the Hancock's most famous neighbors: the Prudential Tower).

Cobb's design married this Functionalist aesthetic with a refreshing sense of minimalism. The Tower's parallelogram shape lends the building a remarkable sharpness, especially when viewed from a 3/4 angle. Two exceedingly simple notches run the full, vertical length of the building, each one splitting one of the narrow sides into two spears reaching up into infinity. In the early morning and early evening, these notches catch the light of the sun as it rises and then falls. It's really remarkable.

One of the greatest temp. jobs I ever had was a season-length position in an asset management firm occupying the Tower's 53rd floor (just about 7 floors from the top). I remember a sense of floating above all else. The core of the building, of course, is opaque, but everything lining the building's periphery is just pure, unadulterated sky.

On a windy day, I could hear the tuned dampers shifting slowly on the 58th floor, groaning faintly like two giants watching over the building beneath them, protecting it from the ever encroaching laws of nature.

And it was impossibly beautiful.