The booted feet of the author and her father feigning bravery on The Ledge of the Sears Tower: photo: katharine morales
Straining to see further, vying for a vantage point with stubborn strangers and hyper children of knee height always in the way, the crowd gathered in the observation deck at the Sears Tower in Chicago is getting restive. Manners and feigned patience are the only factors stopping a riot thousands of feet above street level. My father and I sat through an educational film about the rivalry between New York City and Chicago, we stood up against cardboard cutouts of Michael Jordan and Barak Obama, with graphs detailing how many presidents tall is the building in which we stand (283), we paid more money than these things are worth, and now we are pushing our way to the windows for the real attraction — the heart fluttering, knee-weakening, stomach-churning, mind-reeling “Ledge.” These four glass capsules jut 4-1/2 feet from the tower’s 103rd floor, allowing for unprecedented views. Lake Michigan is a vast turquoise backdrop outlined by Indiana’s hills, and the ball park the White Sox call home is dotted with pinpricks of stadium light. But it’s hard to look out when we are trying so hard to not look down — down past our shoes, down a vertical quarter mile to the ants walking by on Wacker Drive. The sensation brings you to your knees, if only at a desperately vain attempt to get that much closer to the blessed floor, and the words plunge, plummet, and smash come dauntingly to mind.
The Ledge in Sears’ Tower Skydeck is among the latest of a trend among tourist attractions engineers, architects and land owners have taken on in recent years, and the is not the only gravity defying structure for unrivaled vistas. November 2011 saw the completion of an ingenious, daring, and downright scary attraction-turned-adventure in Zhangjiajie, China in the province of Hunan. A glass bridge towering 4,700 feet over a steep drop into a canyon encircles the cliffs of Tianmen Mountain. Possibly inspired by the Grand Canyon’s Skywalk, built in 2007, Hunan’s bridge rises more than a 1,000 higher than Arizona’s Skywalk, which hovers over a drop of a paltry 3,600 feet.
The Grand Canyon Skywalk lures the bold tourist willing to stroll along a glass walkway thousands of feet above the canyon floor.
These marvels of engineering in glass test not only the compressive strength of red limestone (as in Arizona’s Skywalk) or the mettle of tourists, but the future of glass as a viable architectural tool. The Skydeck website attributes the inspiration for the Ledge to forehead prints left by curious visitors on the windows. Zhiangjiajie’s Skywalk solves these issues by requiring tourists to wear disposable protective shoe coverings. The use of glass in recent years as a functional material, as well as a visually striking one, speaks volumes. This New York Times article by Henry Fountain details the chemical and physical advances made by engineers in the past decade that allow for dazzling, sustainable and tough glass structures. Not like the one-off glass houses of old, a la Frank Gehry, these double paned, triple bonded, iron enforced glass works are strong like steel – which is hard to remember when the only thing keeping you from plunging 1000s of feet below is a material that has oft been used as a metaphor for fragility.
view of glass bridge Tianmen mountain cliff face from canyon bottom; image courtesy of China Foto Press
-Katharine Morales