Show caves are generally not very good concerning accessibility. That's easy to understand, natural caves have low ceilings, uneven floor, descents, and narrow passages. To develop such a cave in a highly accessible way generally collides with nature protection, as it would require massive destruction in the cave. Nevertheless, we find it important to give an idea which level of ability is required to visit a cave. Unfortunately this kind of information is published rarely, so we depend on reviews of visitors.
Since show caves which offer guided tours for wheelchair users are so rare, we have compiled a list. Out of 1456 caves currently listed on showcaves.com, there are just 46 . These are all show caves of which we know that it is possible to take part in a guided tour with a wheelchair. Of course, there are often restrictions. In many cases you have to book in advance. In some caves its required to use a special wheelchair which is provided, or there is a small obstacle like a staircase at the entrance, which is overcome with a little help. Also, you may not be able to see the whole tour and have to wait at some point. Or there is only one tour which is accessible and the others are not.
We only list caves here, because all kinds of artificial subterranea do not have the same problems. Most mine tunnels are already horizontal, the same goes for cellars or cave houses. That's the idea of such a structure. It has a flat floor, so you can use carts or even drive around with lorries. If wee added those to this list it would be very long. Nevertheless, there are obstacles in the form of staircases even in artificial objects and by far not all are accessible.