In the locally well-known cave of Askondo, near the industrial town of Mañaria in northwest Spain, researchers unexpectedly discovered faint red images of horses and hand prints, dating back some 25,000 years.
     Diego Garate of the Archaeological Museum of Biscay in Bilbao, and Joseba Rios-Garaizar of the Max Planck Institute, entered the cave to search for bones, tools, and other artefacts. Only on their way out of the cave did they noticed the paintings that they and many others had missed before. Unlike many other caves, Askondo can still be entered by the same passage used by the painters of the cave.
     Says Garate, "The paintings located in the cave of Askondo could be contemporary to the first stage of decoration of Altamira" [where the first European cave art was discovered in 1879]. "There are other caves in the north of Spain with red painted animals near the entrance of the cave, in zones of semi-darkness." [In contrast to many of the more famous caves in Europe, where images are found in the darkest regions.]
     Garate explains, "The advantage of the cave of Askondo is that it is halfway between [Spain and France]. This is reflected in the iconography - with some rather Pyrenean (French) elements like bones fitted into the walls, and some Cantabrian (Spanish) elements like twin outlines - and with other more general elements that appear on a large scale throughout Western Europe like the horses with 'duck bills', or the hand prints."

National Geographic News (13 May 2011)