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 Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.