Mas de Las Fons castle was built from the 12th to 15th centuries. The Romanesque chapel dates from the 12th century.
The Church of the Savior on Spilled Blood is one of the main sights of St. Petersburg. The church was built on the site where Tsar Alexander II was assassinated and was dedicated in his memory. Construction began in 1883 under Alexander III, as a memorial to his father, Alexander II. Work progressed slowly and was finally completed during the reign of Nicholas II in 1907. Funding was provided by the Imperial family with the support of many private donors.
Architecturally, the Cathedral differs from St. Petersburg's other structures. The city's architecture is predominantly Baroque and Neoclassical, but the Savior on Blood harks back to medieval Russian architecture in the spirit of romantic nationalism. It intentionally resembles the 17th-century Yaroslavl churches and the celebrated St. Basil's Cathedral in Moscow.
The Church contains over 7500 square metres of mosaics — according to its restorers, more than any other church in the world. The interior was designed by some of the most celebrated Russian artists of the day — including Viktor Vasnetsov, Mikhail Nesterov and Mikhail Vrubel — but the church's chief architect, Alfred Alexandrovich Parland, was relatively little-known (born in St. Petersburg in 1842 in a Baltic-German Lutheran family). Perhaps not surprisingly, the Church's construction ran well over budget, having been estimated at 3.6 million roubles but ending up costing over 4.6 million. The walls and ceilings inside the Church are completely covered in intricately detailed mosaics — the main pictures being biblical scenes or figures — but with very fine patterned borders setting off each picture.
In the aftermath of the Russian Revolution, the church was ransacked and looted, badly damaging its interior. The Soviet government closed the church in the early 1930s. During the Second World War when many people were starving due to the Siege of Leningrad by Nazi German military forces, the church was used as a temporary morgue for those who died in combat and from starvation and illness. The church suffered significant damage. After the war, it was used as a warehouse for vegetables, leading to the sardonic name of Saviour on Potatoes.
In July 1970, management of the Church passed to Saint Isaac's Cathedral (then used as a highly profitable museum) and proceeds from the Cathedral were funneled back into restoring the Church. It was reopened in August 1997, after 27 years of restoration, but has not been reconsecrated and does not function as a full-time place of worship; it is a Museum of Mosaics. Even before the Revolution it never functioned as a public place of worship; having been dedicated exclusively to the memory of the assassinated tsar, the only services were panikhidas (memorial services). The Church is now one of the main tourist attractions in St. Petersburg.