The Dolmen are megalithic treasures dated all the way back to 3000 plus, years ago, and are situated a few kilometers apart in Dereio and Roussa. Follow the road that connect Little Dereio with Roussa and on a hill full of oak trees you will find them at a specially designated and protected area. Dolmens are megalithic monuments which are actually tombs from early iron age, these dated at 900-800 BCE. Inside the Dolmens were placed large ceramic urns with the ashes of the departed. Continuing on the road from Roussa towards Hillia (called “Hill-ya” by the locals) at some point the paved road comes to a halt and you’ll have to follow for about 1000 meters a dirt road up to a hill marked from the Archaeological Agency.
If you hike the slope there, among many oak trees you’ll find huge rocks with engraved runes on them. There are also engraved sketches of humans, reptiles, birds and other symbols rumored to have magical abilities that fended off spirits. Those rock writings are dated somewhere in between the late Copper Age up to the early Iron Age, somewhere in between 1100-900 BCE. Some of the human figures that are clearly visible appear to be dancing, and some of the birds are swallows so it is hypothesized that part of it might be a depiction of celebration of the spring coming.
Following the road to Hillia you will discover various fossils, some fossilized tree trunks are even visible from the road. The hilltop of Hillia is a sacred place for local Pomaks and are gathered there to celebrate the Yagla-Bairam (which coincides  with the celebration of Prophitis Elias), when the traditional wrestling takes place among the men of the settlement.