If you follow the road towards the south from Kamilari, through the villages of Sivas and Listaros, passing by the monastery of Odigitria, take a right turn here and follow the signs of "Martsalo". You can walk from Moni Odigitrias in probably 2 hours time.
This gorge is remarkable because of its old troglodytic church, where a mass is celebrated every 15th of August. The church is supposed to have been used as a shelter by first Christians hunted by the Romans. There is a "pilgrimage" from local people every year in spring. It's a beautiful view on the gorge that you see from above when you stand in front of the church.
Thanks to the mountains all around, which protect the place from the north and to its south orientation, Martsalo also shelters a thicket of endemic palm trees of the same species than those of Preveli and Vaï. This makes it a quite exceptional place which, from the top of the cliff, somehow looks like an oasis.
The Martsalo gorge is in the same area as Agiofarango gorge and you could easily walk one after the other gorge in one day trip.