Close to the Catacombs of San Callisto are the large and impressive Catacombs of Domitilla (named after Saint Domitilla), spread over 15 kilometres of underground caves.
The Domitilla Catacombs are unique in that they are the oldest of Rome's underground burial networks, and the only ones to still contain bones. They are also the best preserved and one of the most extensive of all the catacombs. Included in their passages are a 2nd-century fresco of the Last Supper and other valuable artifacts. There are almost 150,000 bodies buried in the Catacombs of St. Domitilla.
They are the only catacombs that have a subterranean basilica; entrance to the catacombs is achieved through this sunken 4th-century church, at via delle Sette Chiese 282. In the past, the basilica had become unsafe, and was abandoned in the 9th century. It was rediscovered in 1593, and much of it was reconstructed in 1872.
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.