Breaking up the flat agricultural areas of Argentina’s Pampas is a guitar formed entirely out of trees. Stretching for 2/3 of a mile (1km), the multi-colored instrument was created by one Argentine farmer to memorialize his wife. Crushed by the loss of his love, a few years later Pedro Martin Ureta (owner) began working on designing a guitar in his field that could be seen from above by airplane. He settled on the design because his late wife loved the instrument and he wanted to memorialize her on his land.
If anyone wants to check it in a map software or site, the coords are -33.867865, -63.988014. I got this info from a blog entry written by one of Pedro and Graciela’s children (Graciela was the above mentioned late wife.) It’s ~300km to the south of Córdoba city, same province.