Pentre Ifan contains and gives its name to the largest and best preserved neolithic dolmen in Wales. As it now stands, the Pentre Ifan Dolmen is a collection of seven principal stones. The largest is the huge capstone, 5 m long, 2.4 m wide and 0.9 m thick. It is estimated to weigh 16 tonnes and rests on the tips of three other stones, some 2.5 m off the ground. There are six upright stones, three of which support the capstone. Of the remaining three, two portal stones form an entrance and the third, at an angle, appears to block the doorway.
The dolmen dates from around 3500 BC, and has traditionally been identified as a communal burial. Under this theory the existing stones formed the portal and main chamber of the tomb, which would originally have been covered by a large mound of stones about 30 m long and 17 m wide. Some of the kerbstones, marking the edge of the mound, have been identified during excavations. The stone chamber was at the southern end of the long mound, which stretched off to the north. Very little of the material that formed the mound remains. Some of the stones have been scattered, but at least seven are in their original position. An elaborate entrance façade surrounding the portal, which may have been a later addition, was built with carefully constructed dry stone walling. Individual burials are thought to have been made within the stone chamber, which would be re-used many times. No traces of bones were found in the tomb, raising the possibility that they were subsequently transferred elsewhere.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.