RT @Learn_Things: Before the invention of radar, aircraft were detected by listening. https://t.co/O5hFIjOOv8 0 atbildes
Mārtiņš Galvanovskis (2016-11-07 09:26:50) |
RT @Learn_Things: Before the invention of radar, aircraft were detected by listening. https://t.co/O5hFIjOOv8 |