Yes, of course. It was a combination of flying saucers and Nikola Tesla.
You see, Tesla obtained information (which to this day remains classified and TOP secret) that space aliens were going to attack Earth with a fleet of flying saucers. Tesla immediately developed a super laser anti-spacecraft weapon that he used to destroy one of the space aliens' scout ships, causing the Tunguska explosion. This so frightened the space aliens that they called off the attack and informed their home planet in the Alpha Centauri system (using sub-space radio) that the Earthlings were far too dangerous to mess with.