W 2 half. 18th century. the castle was the main center of political and cultural life in Poland. W 1773 r. the National Education Commission held debates in the castle and that year the Partition Sejm was held, famous for the dramatic speech of Tadeusz Rejtan. The famous "Thursday Dinners" were held, to which the king invited representatives of science and culture, and the development of the economy was discussed, science and culture in the country. Systemic reforms were drafted, the crowning achievement of which was the Constitution passed by the Grand Seym 3 house.

After the last reconstruction, the rooms have survived without major changes (not counting the export of works of art and historical memorabilia to Moscow and St. Petersburg, moreover, they were largely reclaimed after the Treaty of Riga) until World War II, during which the Royal Castle was first plundered by the Nazis, and then completely ruined (X-XII 1944 r.). It was recreated thanks to the efforts of the entire Polish society and donors from abroad in the 1970s. They stand out among the interiors open to the public: the rooms of King Stanisław August Poniatowski, Prospect Hall with the band 23 views of Warsaw painted by Canaletto, Audience Hall with paintings by Bacciarelli and the Royal Chapel), Great Suite (m.in. The Marble Room with the post of Polish kings painted by Bacciarelli, Knight's Hall with historical paintings by Bacciarelli and 22 bronze busts of outstanding Poles, The Assamblowa Room is decorated with columns and mirrors, Council Room – place of "Thursday dinners"), parliamentary halls (Chamber of Deputies – place of the session of the Great Seym, Senator's Room – one of the two places where the Constitution is sworn in 3 house).

To the south. The wings of the castle are adjoined by the Royal Library built in 2 half. 18th century. on the initiative of King Stanisław August Poniatowski according to the design. Dominik Merlini, Jan Christian Kamsetzer and Jakub Kubicki. Near the library, on the edge of the escarpment, the "Pod Blachą" palace is located, built in 1720 r. for Jerzy Dominik Lubomirski – of the Crown Chamberlain. The name comes from a roof covering that was rare at that time. The palace took over in 1777 r. king Stanisław August Poniatowski, who commissioned Dominik Merlini to remodel the interior. We go to ul. Świętojańska. We enter the area of ​​the Old Town, which was probably established at the turn of the 13th and 14th centuries. It occupies a relatively small area surrounded by defensive walls. There is a rectangular market in the middle of the complex, from which the streets that form the network regularly come out. This assumption has remained virtually unchanged to this day. Initially, the buildings were wooden. Gradually, especially after the fire in 1607 r., wooden houses were replaced with brick tenement houses. From the end of the 18th century to the beginning of. XX w. The Old Town experienced a regression, many buildings fell into decline at that time. W 1906 r. an attempt was made to gradually save the most valuable tenement houses. W 1928 r. tenement houses in the market square gained new paintings by Polish artists: F. Kowarski, T. Gronowski, W. Borowski, S. Rzecki, L. Slendziński, WITH. Stryjeńska et al. During the Warsaw Uprising, the Old Town was demolished in 90%. The reconstruction after the war was completed in 1963 r.