The Crooked Forest, known in Polish as Krzywy Las, sits near the town of Gryfino in western Poland. It holds roughly 400 pine trees whose trunks bend sharply at the base before curving back upward. The trees were planted in the 1930s, and the cause of the distinctive curvature remains unexplained.
An infestation of the pine shoot moth produces a very similar structure. The eggs are laid into the shoot killing it. The pine reacts by producing a new shoot on the side which curles towards the vertical again producing these characteristic bends in pines.
See here for a very early stage: