I am a lover of caves. My interest in them started when I was a kid and my friends and sister and I took a spelunking class that brought us underground to explore the local caverns. While they weren't as awe-inspiring as some of those I've seen since, that first experience of climbing down a long rope into utter darkness and crawling around in tight passages through the rocks left me forever wanting more.
Grutas de Mira de Aire is one of Portugal's 7 natural wonders. The word grutas means "caves" in English, and if you have the opportunity to spend time in this area of Portugal, you'll see a quite a few billboards advertising other grutas as well. I originally read about this destination somewhere on a tourist website and as soon as I saw a few of the photos, I knew I had to visit. I wasn't expecting it to be as amazing as Carlsbad Caverns or Mammoth Caves, but the experience far exceeded my imaginings.
Grutas de Mira de Aire may be accessible by public transport, but we took a car which I believe would probably be the easiest way to get there. It is fully equipped as a tourist destination with a restaurant, petting zoo, several historical markers, a waterpark (summer only), and reasonably priced cabins to stay the night. Parking is free and plentiful. Hours of operation are from 9:30 AM to 5:30 PM in the winter and later in the spring and summer months.
The tour of the caves is €6.50 for adults and €3.80 or less for children 12 and under. The tour is about an hour and starts with a video in Portuguese with English subtitles explaining how the caves were formed over the millennia. At the end of the video, everyone follows the tour leader down into the caves. The tour itself was in Portuguese, but you don't need to understand the language to enjoy the awesomeness of the caves. One caveat however: I would not recommend this tour if you are afraid of enclosed spaces or have a difficult time climbing up and down stairs, nor would it really be suitable for infants (unless you can carry them in such a way that your hands are free). The steps are mostly carved from rock and can be wet and very slippery in places.
At the end of the tour are several waterfalls lit by colored lights in a small underground lake. Once you've completed your trek through the grutas, everyone boards the two elevators that take you up to the surface and into the obligatory gift shop. Once we emerged, we spent some time checking out all the adorable animals in the petting zoo. The geese were my favorite as they were super friendly and seemed to have declared war against my shoelaces.
If you want to visit one of Portugal's greatest wonders, make sure to put aside a day to see Grutas de Mira de Aire, found here on Google Maps. It's one of those amazing experiences that you'll remember forever.