What was the first credible UFO incident?

What do you think was the first credible event in UFOology? This is a pretty broad category--I'm counting close encounters, UFO sightings, UFO crashes, pretty much any incident. Most people these days start with Roswell, but the thread on the Battle of Los Angeles made me start thinking of the even shadowier cases pre-Roswell.

Personally, I don't find ancient sightings very credible. I know there are schools of thought that go back to ancient astronauts, and to that I say "Maybe". The stories have just gone through too many layers and generations of translation and distortion and I can't really make up my mind. It's certainly possible.

I'd like to believe in the Auroria Incident in Aurora, Texas, 1897. It's a great story--a mysterious blimp like craft crashes into a windmill and breaks up when it hits the ground. They find an alien body and even give it a burial in the local boneyard. So, I dunno. Not sure if I believe it but I sure like it. It's a great story.

In the early 20th century, the Tunguska Event of 1908 is where my juices really start flowing. Something huge and radioactive crashed into a whole lot of cold, white Siberian nothing and put the ecosystem in revolt for a pretty long time. It could've been an asteroid or even a coment, but whatever it was had the military and establishment scientists scrambling to get the site cleaned up and evidence removed.

After that, I guess the Battle of Los Angeles is the first UFO event that I look at and say "Alright. No amount of argument has managed to persuade me that this was not, in all likelihood, a really scary alien encounter". So for me, I guess, the definitive beginning of the UFO phenomenon, the first point where I say "Yeah. No doubt in my mind, those were flying saucers piloted by space aliens" was 1942, the Battle of Los Angeles.

How about you?