 Cyclopean is the term normally applied to the masonry characteristics of Mycenaean fortification systems and describes walls built of large , unworked boulders more than 8 m ( 26 ft ) thick and weighing several metric tonnes . They were roughly fitted together without the use of mortar or clay to bind them , though smaller hunks of limestone fill the interstices . Their placement formed a polygonal pattern giving the curtain wall an irregular but imposing appearance . At the top it would have been wide enough for a walkway with a narrow protective parapet on the outer edge and with hoop @-@ like crenellations . The term Cyclopean was derived by the latter Greeks of the Classical era who believed that only the mythical giants , the Cyclops , could have constructed such megalithic structures . On the other hand , cut stone masonry is used only in and around gateways . Another typical feature of Mycenaean megalithic construction was the use of a relieving triangle above a lintel block ; an opening , often triangular , designed to reduce the weight over the lintel . The space was filled with some lighter stone . 
