Google reportedly tried - and failed - to build a jetpack.
The head of the search giant's 'X' lab said that the team tried to build a jetpack that wasn't "a death trap" but were not ultimately able to make the sums add up.
Astro Teller told Techcrunch Disrupt in new York that the lab ditches 100 similar projects every year because they try so many things - and are so willing to drop those that don't work.
Int he case of the jetpack he said "the problem is that it is going to be so power inefficient. I just couldn't live with that...it would be as loud as a motorcycle."
The key to a sustainable jetpack that acutally works, he says, is a new form of battery pack able to last longer, and provide more juice.
"A 10x improvement in energy density...would change the world so radically we can't even see," he told the conference.
Alas - if Google can't build a jetpack it looks like no one can. And indeed history is resplendent with glorious failures. Check out 11 people who also tried to get there - and the reasons that they failed.