initiated by Ion Mincu and taken over by other prestigious architects who capitalise important references of Romanian laic and medieval ecclesiastical architecture (for example the Mogoșoaia Palace, the Stavropoleos Church or the disappeared church of Văcărești Monastery) and Romanian folk motifs. Two buildings from this time are the Crețulescu Palace, housing cultural institutions including UNESCO's European Centre for Higher Education, and the Cotroceni Palace, the residence of the Romanian President. Many large-scale constructions such as the Gara de Nord, the busiest railway station in the city, National Bank of Romania's headquarters, and the Telephones Company Building date from these times. In the 2000s, some historic buildings in the city centre underwent restoration. In some residential areas of the city, particularly in high-income central and northern districts, turn-of-the-20th-century villas were mostly restored beginning in the late 1990s. Communist era architecture A major part of Bucharest's architecture is made up of buildings constructed during the Communist era replacing the historical architecture with high-density apartment blocks – significant portions of the historic centre of Bucharest were demolished to construct one of the largest buildings in the world, the Palace of the Parliament (then officially called the House of the Republic). In Nicolae Ceaușescu's project of systematization, new buildings were built in previously historical areas, which were razed and then built upon. One of the singular examples of this type of architecture is Centrul Civic, a development that replaced a major part of Bucharest's historic city centre with giant utilitarian buildings, mainly with marble or travertine façades, inspired by North Korean architecture. The mass demolitions that occurred in the 1980s, under which an overall area of eight square kilometres of the historic centre of Bucharest were levelled, including monasteries, churches, synagogues, a hospital, and a noted Art Deco sports stadium, changed drastically the appearance of the city. Communist-era architecture can also be found in Bucharest's residential districts, mainly in blocuri, which are high-density apartment blocks that house the majority of the city's population. Initially, these apartment blocks started to be constructed in the 1960s, on relatively empty areas and fields (good examples include Pajura, Drumul Taberei, Berceni and Titan), however with the 1970s, they mostly targeted peripheral neighbourhoods such as Colentina, Pantelimon, Militari and Rahova. Construction of these apartment blocks were also often randomised, for instance some small streets were demolished and later widened with the blocks being built next to them, but other