In 1944 a young Estonian boy noticed tracks leading into Lake Kurtna Matasjary. To the boy, they looked as if they were tank tracks. But when he searched around the lake, he saw that there were none leading out of it.
When the boy told his community elders, no one believed him. Despite this, the boy kept coming to the lake for two months. During his trips, he noticed bubbles gurgling out in the middle of the lake. Something was breathing under there, or so he thought.
Although the child was curious he had no one to investigate. He just had to put the mystery out of his head. At least he did until he decided to do something about it 50 years later.