Dr. Kevin R. Stone, an orthopedic surgeon who lives in San Francisco, first had his idea for a life-saving harness 10 years ago today, on September 11, 2001.  

"I started thinking about it the moment I saw people holding hands and jumping out windows [of the World Trade Center]," Stone told The Indianapolis Star last month. 

In 2006, Stone brought to market the Rescue Reel, a device that allows someone of any size to be safely lowered to the ground from a height of up to 1,000 feet. Using a Kevlar cord, which is wound around a metal reel, a harnessed user can rappel to the ground in an emergency. 

Another product, the SeatChute, developed by Peter Hilsenbeck of Chandler, Arizona, was created with similar intentions—it's an office chair with a parachute that can be deployed from atop an office building. 

Catastrophe is a powerful agent for invention. More than gadgets like the Rescue Reel and SeatChute, which conjure up an almost super-hero-like fantasy, ever since September 11 entrepreneurs and scientists (and some who wear both hats) have been quietly plodding away at a variety of ideas, mechanisms, and processes designed to make the world a better, safer place.

The devastation catalyzed new concepts in community, industrial design, architecture, and safety protocols that may serve to prevent—or at least mitigate—future calamities. Similarly Hurricane Katrina inspired new ideas about urban planning, like grinding up storm debris to raise city elevation. 

Scott Heiferman, co-founder and CEO of Meetup, a New York-based web start-up that facilitates in-person meetings for people with shared interests, says the idea for his company was spawned by September 11. 

"When the towers fell, I found myself talking to more neighbors in the days after 9/11 than ever before," he says in an e-mail statement. "People said hello to neighbors (next-door and across the city) who they'd normally ignore. People were looking after each other, helping each other, and meeting up with each other. A lot of people were thinking that maybe 9/11 could bring people together in a lasting way."

Nine months later Heiferman launched Meetup, which now has almost 10 million users and 100,000 Meetup groups around the world. "Meetups aren't about 9/11, but they may not be happening if it weren't for 9/11," he says. 

Garth Rockcastle, a professor of architecture at the University of Maryland, says: "When events like 9/11 occur they accelerate and intensify that ongoing innovation. I think that context needs to be appreciated."

Take, for instance, one of the first examples of innovations to arise, quite literally, from the rubble itself: One World Trade Center, an iconic skyscraper that will loom 1,776 feet above Ground Zero—49 feet taller than the spire of the original 1 WTC. 

A new documentary by NOVA, presented by PBS, looks at how 1 WTC architect David Childs is engineering this new breed of skyscraper that is able to withstand nearly any type of attack—including a high-speed impact from a jet—while maintaining the glass and open floor-plan aesthetic desired by developers and tenants. 

Childs explains that the center spine of the building is made out of a new type of concrete—one that is strong enough to accommodate a 175,00-pound load on a concrete cylinder just four inches in diameter. In addition, stairwells are wider, the first 19-stories are "built like a bunker," and the exterior glass is bomb-resistant. 

When the towers fell 10 years ago today, search robots were deployed to the scene to move debris and locate potential survivors. Back then, writes Susan Hassler in IEEE Spectrum, search and rescue robots were still in their nascent design. Firms like iRobot Corp. and Foster-Miller, which sent robots to Ground Zero, took the experience to improve upon their robot designs. There's even a school for this type of engineering now. The Center for Robotic-Assisted Search and Rescue at the University of Texas A&M opened shortly after September 11—because of September 11. 

"Before 9/11 the idea that intelligent robots could help save lives at disaster sites was dismissed as science fiction. But not after," Hassler writes. "While they saved no one, these robots were able to traverse some of the vast debris field, going where humans and dogs dared not, demonstrating indisputably that they weren't toys or expensive curiosities but viable machines capable of standing in for humans in dangerous situations." 

And other innovations, like the Nano Air Vehicle—a reconnaissance vehicle the size (and shape) of a hummingbird—is now in development, thanks to a nearly-$50 billion Department of Homeland Security budget that encourages defense contractors to drum up new ideas ever since September 11. 

Certainly these innovations do nothing to reclaim the lives of those who lost everything in the September 11 attack. But, as Hassler puts it, the hope is that at least "some good can come from so much misery."