We got to go the caverns cut into the limestone with a guide who did not speak any english...
but she pointed out a number of things 

Our wee wooden boat had 10 good sized people in it, but our rower (elderly woman)
had no problem moving us for over an hour.
 At some points during the tour the water became very shallow and I thought for sure that
some of the men were going to have to get out and push...but that never occurred...thankfully