The lower level of the site's Museum covers the highly varied geology of the island whilst the upper levels work chronologically through the islands history from a Rhinoceros skull, through its earliest human inhabitants to a hoard of coins from the Roman occupation. There are also fascinating displays of objects including a Bronze Age hoard (above) and polished stone axes (right).
At the core of the site is a Neolithic passage grave that is now surmounted by a medieval chapel (left). The cruciform passage grave is over 5,000 years old and, with its largely intact mound, is considered to be one of the finest examples in Europe.
The eastern side slab of the grave's northern side chamber has at least 24 cup marks on its eastern face. This is the only rock art in the structure and despite the fact that their significance is long lost the time invested in their making testifies to their importance to the people who placed their dead in this special place.
Like the Christian chapel above the passage grave is aligned on an east west axis, in this case to allow the sunrise at the equinoxes to penetrate to the heart of the chamber complex.
The original structure of the chapel dates from the Norman period. The original building is now divided into two chapels and a rotunda with a ring crypt beneath.
The Jerusalem Chapel has two very feint ceiling paintings of angels from c. 1520. Quite different to the rock art below but undoubtedly equally significant to those who worshiped there.
Although there is no longer any evidence of its presence the chapel was extended around 1792 to form the Prince's Tower - a private dwelling in the form of a miniature Gothic castle. The Tower fell into disuse and was demolished in 1924.
The site does much educational work and includes a reconstruction of a Neolithic house, a group of querns for grinding grain to flour and a replica log boat. A German Command Bunker, elsewhere in the grounds, houses a memorial to the slave-workers of the second World War.