The visitors could hire one of the three detectors to search for the coral- reef beneath the earth. This was done by walking over the meadow moving the detector slowly backwards and forwards.
If the detector located a subterranean cavern beneath the meadow (i.e. was in close proximity to a signal) you heard a beep and the instrument began to scan into the depths. On reaching the bottom of the area being scanned, images and movies of what could be seen were displayed on the monitor attached to the detector. Further information about the reef could be heard over head phones If you moved away from the signal, the meadow once again appeared on the monitor.