We visited the caves on September 4th with Spanish friends of ours who planned a 6 day visit of the Basque Country. We took the last tour out that day at 6:00 in the evening. To get to the caves, you drive on these lovely winding mountain roads that take you through some charming villages. The turn off for the caves takes you up through the mountain (about a 3 KM drive) to get to the cave's entrance. When you get to the visitor's center, there's a train (about a 3 minute train ride) that takes you into the depths of the caves. Then, there's about a 500 foot walk to the caves' entrance. Once you enter the caves, the sight is staggeringly beautiful -- stalagtites and stalagmites abound at every turn. You don't know where to look first. In one room, classical musical was playing as we gazed at the delicate shapes of these natural formations. My only regret is that you are absolutely forbidden to take photos. And, the only negative is that the tours are only in Spanish. While I speak some Spanish and was able to understand about 50% of what was said, my husband doesn't speak much at all and didn't understand anything. However, by asking our guide, we found out that she spoke perfect English given that her husband was from GB. So, after each talk/segment given in Spanish, we would walk with her while she repeated the highlights in English of what she explained to the group. While she didn't translate 100% of what she said in Spanish, we got most of it. So, if you go there and you don't speak English, ask the guide if he or she speaks English. Chances are, you'll be in luck.
By the way, I highly recommend that you spend the night in Ruente at the hotel del torre. It's a typical Spanish Cassona (inn) not too far from the caves . . . very charming. The village was only a 20 minute drive from the caves.
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