Zemi Valley and El Nazar Church
This valley has the advantage of not having many tourists.But it is a bit longer than others and about 5 km.It contains a church on the 500 600 m from start.
You certainly do need someone to give you directions at the start, (even you can feel unsafe but dont worry:) as the tiny path where it starts can be quite easily missed. Basically as soon as you hear running water you are not far from where it starts. We followed the stream for all of its course, which we now found out was a far longer route. We ended up trekking 12km as opposed to the 5km we had expected.
The start is amazing, caves, stream, nature, no one else around, a paradise. However about half way the cave houses are less impressive and it becomes about the walk itself.
As pointed out by others, on the second half of the walk there are signs or agriculture, as you will cross several used areas of land during the journey.
If you have time and feel energetic you can walk this long valley but if you are short of time I suggest you to walk to El Nazar Church. It is about 500 or 600 metres in the valley on the left side you will see a stone sign showing its way. It is 5 TL to enter this side.You can pay and see but you can also see such Churches in the other valleys and 7 churches in Open air museum.
Also of note, if it rained the day before take appropriate footwear and walking sticks, as you do need to cross a few muddy sections along the stream.
Would recommend for those a little more adventurous.