The Great dolmen of Dwasieden was excavated in 1970 by Ewald Schuldt. The megalithic site of the Funnelbeaker culture was constructed between 3500 and 2800 B.C. Of the 54 kerb stones - including the four guardian stones - 41 have survived. The rectangular, roughly east-west oriented chamber at the wide end of the frame, with its western entrance and porch consists of seven supporting stones, a half stone the height of the uprights and five slabs, on which there are three large (on the chamber) and three small capstones. Only the central capstone of the chamber is missing. One of the four guardian stones at the southwest end, which had already been overturned in the past, has 40 cup marks, one of the kerb stones has three more. The site is a prime example of the porch dolmen, typical of this region. A two-metre-long porch runs past the support-high half stone to the 4.0 metre long, 1.7 metre wide and 1.4 metre high chamber. The hall consists of red sandstone slabs, annealed flint and a clay floor.
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.