The cache is located at Nahal Glilot (or Nahal Glil-Yam). You can learn all about it here.
Note: Please don't attempt this one during rain, if the river is flowing or if you're claustrophobic.
At the posted coordinates you'll find a nice shaded parking location.
From there go north to the river path entrance.
Once you're on the river path say hello to the river guard, and go left, south-west, for about 60-70 steps. If you pass the 'Safe!' Graffiti, turn back.
To your left you'll see the watching eye. Let's enter it... We'll walk pass the eye for about 100-200 meters. Get ready.
To reach the cache count about 40 stages of the path (each stage is about 3 meters). It will be on your left.
For the courageous FTF, there is a ghost of a TB waiting inside, 40 stages deep after the cache location.
Edit: Kudos @hetzroni the brave! The ghost has been safely retrieved from the deep.
Have fun!