The colossal Heidenreichstein castle situated in the moorlands to the northwest of the Waldviertel is the largest and best preserved medieval water castle in Lower Austria. The oldest parts of the castle are dated back to the 12th century. It has never been in enemy hands since its construction. The walls of the four wings, the three corner turrets and the keep are up to four metres thick. A guided tour through the three-storey living apartments with spiral staircase and arcades discloses highly remarkable interior fittings including Gothic furniture, articles of daily life and portrait paintings.
The Basilica of Santa Maria in Trastevere is one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140-43. The first sanctuary was built in 221 and 227 by Pope Callixtus I and later completed by Pope Julius I.
The inscription on the episcopal throne states that this is the first church in Rome dedicated to Mary, mother of Jesus, although some claim that privilege belongs to the Basilica di Santa Maria Maggiore. A Christian house-church was founded here about 220 by Pope Saint Callixtus I (217-222) on the site of the Taberna meritoria, a refuge for retired soldiers. The area was made available for Christian use by Emperor Alexander Severus when he settled a dispute between the Christians and tavern-keepers.
The church underwent two restorations in the fifth and eighth centuries and in 1140-43 it was re-erected on its old foundations under Pope Innocent II.