Crucuno dolmen is one of the most well known dolmens in the Brittany. The rectangular chamber is about 4 metres by 3.5 metres, covered by a single massive capstone which measures over 7 metres in length, perched on top of 9 support stones, with easily enough room to stand upright inside. The enormous capstone is 7.6 metres in length and weighs about 40 tons. Unfortunately, a century or so ago, a house was built right next to it, and this has destroyed all but the last pair of entrance passageway uprights and their capstone. This passageway was recorded in the last century as being 20-25 metres in length, leading away towards the southeast.
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.