When I was a kid, in the library, there were tons of books on UFO's. Back then, you didnt have sciences for faking photos very well, so you could usually see if they were fake or not.
Several that I had seen, that seems ludicrous to me were these photos of what looked like the head of a domed shaped bullet, with a bump or cap at the tip. Oddly, they usually were always filmed or photographed 'on their side' hovering or moving. One group of mountain climbers photographed one, taking a great shot of it, hoving between some mountains very very close to them. It was just sitting there in the sky, near them, as though it was watching them.
The things were usually about 6 feet in diameter, like a little Apollo capsule. Ours do not hover though..
Now, grown up and near 50 years old, I would guess that they were extraterrestrial, and were possibly drones, being they are so small, unless the occupents were the small grays, then you probably had room for 1 in there plus equipment and an engine of some sort..
From some 'leaked?' information on one saucer that they were experimenting on (found disc?), the walls of metal could be tuned to be translucent, like glass or plexi, so they have probably found a way to not need windows, so a disc or 'acorn' wouldnt need windows if they can polarize and make the shell transparent, at least in certain area's.
So many mysteries.. So much to learn and find out..
Bill