As we were not allowed to take pictures inside the Škocjan Caves, we can only barely describe them and suggest you have a look at the official pictures and videos on the park's website: http://www.park-skocjanske-jame.si/en. It was probably the most impressive thing we've ever seen underground. Walking through about 2 kilometres of tunnels, caves and canyon, and a even a bridge hanging 45 meters over the river, we felt like being into a "Lord of the Rings" type of movie. we could at some points see as far as maybe one kilometre underground, or walk through some caves larger than football fields.