A UFO was filmed unintentionally by a man in Bangkok as he was taking photos on a river cruise. It wasn't until he reviewed the photos later that he noticed the unidentified flying object in the pictures.
According to the witness, he was just taking pictures of the skyline as the cruise ship floated by and had no idea what he was actually catching on film.
These kinds of sightings are often the best type because of the spontaneous nature, with no intent on the part of the witness to attempt a hoax. The object in this series of pictures seems to be swooping down, trailing a stream of vapors as it flies.