Call this a lesson in learning what customers want by watching their behavior—even if that conduct goes against millennia of human instincts for self-preservation.

Chicago’s landmark Sears Tower has found a way to enhance its must-see tourist status: a pair of glass-enclosed, glass-bottomed platforms hanging off the 103rd floor of the building’s west façade and offering a 360-degree view (well, minus whatever portion is attached to the building) of a large portion of the city from 1350 feet up.

That’s right. For the $15 price of general admission to the enclosed Sears Skydeck, or $30 for the Fast Pass that puts you in an express line for the elevator, you can now have the sensation of having just fallen out of the building and hanging in the air, Wile E. Coyote-style, for an instant before becoming a little puff of dust on Wacker Drive down below.

As a species, we humans are nuts.

Actually the idea for the enhancement came not from cartoons but from the custodial staff. They complained that their biggest cleaning job up on the Skydeck was washing the forehead prints off the windows. Inspired perhaps by Ferris Bueller, visitors were leaning their foreheads against the glass to look down.

I don’t get it. I hate heights. Growing up around New York, the bane of my existence was out-of-town guests who, having just arrived in the city, immediately wanted to get as much vertical distance from it as they could. In the name of being a good host, I’ve cowered on the Empire State building—both the 86th floor observation deck and that nightmarish little telephone booth of a room some 16 floors above it. I’ve choked on my crème brulee at Windows on the World after getting a wave from a helicopter pilot—a pilot on the job, behind the joystick. I’ve stood in the crown of the Statue of Liberty listening to the rivets creak and pop, trying to bribe my guests with the offer of a Chinese meal on me if we can just leave. Like, NOW.

So don’t ask me how I wound up working on the 96th floor of the Sears Tower doing publishing jobs for a financial firm. For about six months, I worked primarily at a counter pushed up against a floor-to-ceiling window facing that same westward view that Ledge visitors now get. That made the job an interesting mix of grinding tedium and Hitchcockian terror.

Did you know that the Sears, the tallest building in the U.S., is built on giant springs to allow it to sway in a heavy wind? I didn’t, until one blustery March Chicago day when I saw the water sloshing in the men’s room toilets.

I once looked up from my work, my eye caught by what I thought were several large white-roofed buses traveling west toward the United Center arena. They weren’t buses; Michael Jordan and the Bulls were in an NBA playoff game that night, and those were advertising blimps.

No one should ever have to look down on blimps.

I finally quit after one spring lightning storm enveloped the top of the building. It was like living inside the Big Bang, and I didn’t need the paycheck that badly.

Since then I’ve avoided vertical Chicago. In a former job writing for a restaurant trade magazine, that meant steering away from assignments at great restaurants with acrophobia on the menu: The Signature Room on the 95th floor of the Hancock Building, or Everest on the 40th floor of the Stock Exchange. I’ve avoided the Ferris Wheel at Navy Pier because 15 years ago I knew a guy who knew a guy involved in its construction. He swore that a half-inch deviation from blueprints at the base meant that at the top, the thing was five or six feet out of true.

Our Chicago Penton offices are across the street from Donald Trump’s new 80-story hotel and residence complex. When construction neared the 23rd floor, I traded my window office for one on an inner corridor so I wouldn’t have to watch workers eating Big Macs while dangling their feet off I-beams 400 feet in the air.

Nonetheless, hats off to the folks who manage the Sears Tower. Like the guys who decided that people who liked roller coasters would love them if they ran upside-down and backwards, they’ve found a way to build new excitement into a staple attraction.

And for the record, the architectural firm of Skidmore Owings & Merrill, designers of both the Sears Tower and “The Ledge”, say the feature is built to withstand five tons of pressure. “There’s no way you could fit five tons of people into that little enclosure,’ a spokesman said in a press report.

But product enhancement brings its own problems. After one full day of operation, custodians reported a new cleaning issue on “The Ledge”: forehead smears on the floor.

Happy Fourth of July. And now if you’ll excuse me, I have family in town for the holiday weekend. I know what they’re going to ask to do by way of seeing the town.

But they’re going to get a Cubs game and deep-dish pizza, and they’re going to like it.

Call this a lesson in learning what customers want by watching their behavior—even if that conduct goes against millennia of human instincts for self-preservation.

Chicago’s landmark Sears Tower has found a way to enhance its must-see tourist status: a pair of glass-enclosed, glass-bottomed platforms hanging off the 103rd floor of the building’s west façade and offering a 360-degree view (well, minus whatever portion is attached to the building) of a large portion of the city from 1350 feet up.

That’s right. For the $15 price of general admission to the enclosed Sears Skydeck, or $30 for the Fast Pass that puts you in an express line for the elevator, you can now have the sensation of having just fallen out of the building and hanging in the air, Wile E. Coyote-style, for an instant before becoming a little puff of dust on Wacker Drive down below.

As a species, we humans are nuts.

Actually the idea for the enhancement came not from cartoons but from the custodial staff. They complained that their biggest cleaning job up on the Skydeck was washing the forehead prints off the windows. Inspired perhaps by Ferris Bueller, visitors were leaning their foreheads against the glass to look down.

I don’t get it. I hate heights. Growing up around New York, the bane of my existence was out-of-town guests who, having just arrived in the city, immediately wanted to get as much vertical distance from it as they could. In the name of being a good host, I’ve cowered on the Empire State building—both the 86th floor observation deck and that nightmarish little telephone booth of a room some 16 floors above it. I’ve choked on my crème brulee at Windows on the World after getting a wave from a helicopter pilot—a pilot on the job, behind the joystick. I’ve stood in the crown of the Statue of Liberty listening to the rivets creak and pop, trying to bribe my guests with the offer of a Chinese meal on me if we can just leave. Like, NOW.

So don’t ask me how I wound up working on the 96th floor of the Sears Tower doing publishing jobs for a financial firm. For about six months, I worked primarily at a counter pushed up against a floor-to-ceiling window facing that same westward view that Ledge visitors now get. That made the job an interesting mix of grinding tedium and Hitchcockian terror.

Did you know that the Sears, the tallest building in the U.S., is built on giant springs to allow it to sway in a heavy wind? I didn’t, until one blustery March Chicago day when I saw the water sloshing in the men’s room toilets.

I once looked up from my work, my eye caught by what I thought were several large white-roofed buses traveling west toward the United Center arena. They weren’t buses; Michael Jordan and the Bulls were in an NBA playoff game that night, and those were advertising blimps.

No one should ever have to look down on blimps.

I finally quit after one spring lightning storm enveloped the top of the building. It was like living inside the Big Bang, and I didn’t need the paycheck that badly.

Since then I’ve avoided vertical Chicago. In a former job writing for a restaurant trade magazine, that meant steering away from assignments at great restaurants with acrophobia on the menu: The Signature Room on the 95th floor of the Hancock Building, or Everest on the 40th floor of the Stock Exchange. I’ve avoided the Ferris Wheel at Navy Pier because 15 years ago I knew a guy who knew a guy involved in its construction. He swore that a half-inch deviation from blueprints at the base meant that at the top, the thing was five or six feet out of true.

Our Chicago Penton offices are across the street from Donald Trump’s new 80-story hotel and residence complex. When construction neared the 23rd floor, I traded my window office for one on an inner corridor so I wouldn’t have to watch workers eating Big Macs while dangling their feet off I-beams 400 feet in the air.

Nonetheless, hats off to the folks who manage the Sears Tower. Like the guys who decided that people who liked roller coasters would love them if they ran upside-down and backwards, they’ve found a way to build new excitement into a staple attraction.

And for the record, the architectural firm of Skidmore Owings & Merrill, designers of both the Sears Tower and “The Ledge”, say the feature is built to withstand five tons of pressure. “There’s no way you could fit five tons of people into that little enclosure,’ a spokesman said in a press report.

But product enhancement brings its own problems. After one full day of operation, custodians reported a new cleaning issue on “The Ledge”: forehead smears on the floor.

Happy Fourth of July. And now if you’ll excuse me, I have family in town for the holiday weekend. I know what they’re going to ask to do by way of seeing the town.

But they’re going to get a Cubs game and deep-dish pizza, and they’re going to like it.