Felsendome Rabenstein in Saxony is a small mine with two floors, all to see within one longer dive. As far as we remember it’s muddy / silty, so you should take care about fins and percolation.
Individual dates with 2+ divers possible.
Schedule and booking at http://sachsenluft.de/hoehlentauchen/
Hotels next to Rabenstein
A small guesthouse is located next to the mine, infos and bookings at www.felsendome.de