Looking back, from ground level, into the sunken garden and pool.

The upper level is occupied by a museum that is dedicated to the sciences surrounding the study of volcanoes, of geology, and of the measurement of ground deformation (perhaps indicating volcanic activity).

It was said that the tools used to measure ground deformation are so accurate that from Barcelona you could measure a deformation in Granada as small as a 1 Euro coin. So if you ever mislay your change when in Granada, there's a chap in Barcelona who can probably help you find it.