The Clava cairn is a type of Bronze Age circular chamber tomb cairn, named after the group of 3 cairns at Balnuaran of Clava, to the east of Inverness. There are about 50 cairns of this type in an area round about Inverness.
At Balnuaran of Clava itself there is a group of three Bronze Age cairns which lie close together in a line running north east to south west. The tombs at either end are of the passage grave sub-type. The central cairn is of the ring cairn sub-type, and uniquely has stone paths or causeways forming 'rays' radiating out from the platform round the kerbs to three of the standing stones. The cairns incorporate cup and ring mark stones, carved before they were built into the structures. The kerb stones are graded in size and selected for colour, so that the stones are larger and redder to the south west, and smaller and whiter to the north east. All these elements seem to have been constructed as one operation and indicate a complex design rather than ad hoc additions.
The ring round the northern Balnuaran of Clava cairn was measured and analysed by Professor Alexander Thom. He found that the ring was slightly egg-shaped with a complex geometry of circles and ellipses which could be set out around a central triangle, using sizes which are close to whole multiples of what he called the Megalithic yard. While the geometry of the shape is generally accepted, the Megalithic Yard is more controversial.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.