Gathering Intelligence about the Adversary
Surveillance via sophisticated electronic equipment, such as
supercomputers, live reconnaissance satellite video/audio feeds

@@@@Video:
Mathematicians who cracked the Enigma Code (30th Aug' 1941)
Video:
Hiller's Enigma Machine (Must see)
The cracking (breaking) of the secret German Enigma Machine code, helped Britain & Allies, shorten the war by almost 4 years, as they had intelligence about the German plans !
Gathering intelleigence is usually accomplished in 3 ways:-
(1) Using field-agents operating in their country (old-fashioned-espionage);
(2) Listening and intercepting their communication broadcasts (radio-transmissions);
(3) Recieving electronic-data via modern low orbit spy-satellites & UAV (Unmanned Aerial Vehicle) drones;
Video:
How Israel Rules The World Of Cyber Security ? (Information gathering)Video
Modern Satellite In Orbit
Israeli Cartosat-2 / Israeli Heron-TP UCAV / US Predator-B UCAV / US Predator-C Avenger UCAV / US Predator-C Avenger
Video 1)
Predator-C Avenger;
Video 2)
Predator - Gray Eagle;
Video3)
Predator - MQ9 Reaper;
Video 4)
Predator Ground Control Operations
( If video does not play or is removed, type name of video in YouTube video-box & video will re-appear )
Video
Why India wants UCAV from USA ??