Kamena Vourla is a quaint little town on the water with strips of cute tavernas and shopping options. If you plan on actually sticking around, there are a variety of natural springs including the radioactive one which is said to have many health benefits. There is also the Monastery of Metamorfossis tou Sotiros.
Returning from Thessaloniki and Platamona we made a stop in Tempi. The chapel of Agia Paraskevi is built into the rocks in the Tempi Valley, and the end of narrow tunnel is a small spring of holy water. Drink it and make a wish! This was an amazing experience that doesn’t require much time while heading back down to Athens.