Pyrenees, mountain chain of southwestern Europe that consists of flat-topped massifs and folded linear ranges. It stretches from the shores of the Mediterranean Sea on the east to the Bay of Biscay on the Atlantic Ocean on the west.

At its western end it blends imperceptibly into the Cantabrian Mountains along the northern coast of the Iberian Peninsula. Except in a few places, where Spanish territory juts northward or French southward, the crest of the chain marks the boundary between the two countries, though the tiny autonomous principality of Andorra lies among its peaks.

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Poulsen, Thomas M., Ogé, Frédéric. "Pyrenees". Encyclopedia Britannica, 1 Sep. 2026, https://www.britannica.com/place/Pyrenees. Accessed 1 September 2026.