Kolakchal Pass is the place where many Tehranians (or maybe eve Iranians) are hiking every Friday.
This is around 3h hiking from Jamshidie Park (1840m).
There are 2 ways to reach this place:
1-from Jamshidie Park or
2-from Shirpala hut (Darband-Shirpala-Kolakchal Pass)
Both are very ok but in the winter the second one can be very dangerous because of avalanches.