What is the biggest what-if in the history of technology?

Machines that were shelved, defunded, outvoted or burned. Each one is an argument about how different the present could look.

1. 1
   Babbage's Analytical Engine

   A programmable mechanical computer designed in the 1830s and never built in its designer's lifetime.
   1000pts
2. 2
   The Hindenburg

   The airship era ended in 34 seconds at Lakehurst in 1937.
   754pts
3. 3
   Betamax

   Sony's format, widely judged the better picture, beaten in the shops by VHS.
   717pts
4. 4
   Tesla's Wardenclyffe Tower

   Tesla's Long Island tower for worldwide wireless power, abandoned in 1906 when J. P. Morgan stopped paying.
   636pts
5. 5
   Da Vinci's flying machine

   Sketched aerial screws and gliders three centuries before anyone had an engine light enough to fly.
   636pts
6. 6
   Edison's Pearl Street Station

   The 1882 DC station that lit lower Manhattan, and the system that lost the current war.
   538pts
7. 7
   Concorde

   Supersonic passenger flight, retired in 2003, with nothing since flying as fast.
   538pts
8. 8
   Google Glass

   A wearable display pulled from consumer sale in 2015, a decade before the market wanted one.
   418pts
9. 9
   The Saturn V

   Never lost a crew, never flew after 1973, and the production line was shut down.
   418pts
10. 10
    The Library of Alexandria

    Antiquity's great collection, lost in stages, and the standing symbol of knowledge that did not survive.
    269pts
11. 11
    The Xerox Alto

    The 1973 machine with windows, a mouse and Ethernet, which Xerox never turned into a product.
    269pts
12. 12
    The Antikythera mechanism

    A geared Greek astronomical calculator whose sophistication did not reappear for over a thousand years.
    269pts
13. 13
    The Soviet N1 rocket

    The Moon rocket that failed all four launches and ended the Soviet lunar programme.
    269pts
14. 14
    The Segway

    Promised to reshape cities, ended up on tourist tours and out of production in 2020.
    269pts