The Hypogeum of Ħal-Saflieni is a subterranean structure dating to the Saflieni phase (3300-3000 BC) in Maltese prehistory. It is often simply referred to as the Hypogeum, literally meaning 'underground' in Greek. The Hypogeum is thought to have been originally a sanctuary, but it became a necropolis in prehistoric times, and in fact, the remains of more than 7,000 individuals have been found. It is the only known prehistoric underground temple in the world. The Hypogeum is UNESCO World Heritage Site.
The Ħal Saflieni Hypogeum is a complex made up of interconnecting rock-cut chambers set on three distinct levels. Earliest remains at the site date back to about 4000BC, and the complex was used over a span of many centuries, up to c. 2500 BC.
The uppermost level consists of a large hollow with burial chambers on its sides. This hollow was probably originally exposed to the sky and excavations in the early 1990s indicate that there might also have been a monumental structure marking the entrance. A doorway leads to the Middle Level, which contains some of the best known features of the Hypogeum such as the intricate red ochre wall paintings and the beautifully carved features in imitation of architectural elements common in contemporaneous Megalithic Temples. The deepest of the three levels is known as the Lower Level, which is accessed down seven steps in the chamber popularly known as the ‘Holy of Holies’.
The Hypogeum was first opened to visitors in 1908 and since then it has been visited by many thousands of people. Unfortunately, this has had a toll on the delicate microclimate of the site which has affected the preservation of the site and the unique red ochre paintings. For this reason, after a conservation project which saw the site closed for 10 years between 1990 and 2000, a new system was established in which only 10 visitors an hour are allowed in for a maximum of 8 hours a day, complemented by an environmental control system which keeps temperature and humidity at required levels.
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.