Although much has been said and written on the subject of Old Zagreb and even on the development of the Lower Town during the 19th century, research into building activities in Zagreb at the turn of the century or even later has been inadequate and unsatisfactory.

The twentieth century began with the Art Nouveau style, which during its short life, from 1899 until the First World War, was present in the central part of the Lower Town.

The most notable achievements of Zagreb Art Nouveau were the building of the Ethnographical Museum (at 14, Mazurame' Square), the former sanatorium building (Children's Clinic) in Klaiteva Street and the most conspicuous among them, the building of the National and University Library on Marulit Square. The Modernist Movement, led by the architect Viktor Kovacic, presented itself in the building of St. Blaz Church at the corner of Dezelid Avenue and Primorska Street on the eve of the First World War.

At the turn of the century (1902), the city boundary was moved from Medjasuji Square (today's Kvaternik Square) eastwards, and thus Pescenica and Maksimir with their surroundings became part of the city area. Building activities were more intensive in the east part of the town, that is, in the wide-open spaces east of Palmoticeva Street. Zagrebacki Zbor, the forerunner of the Zagreb Fair, organised its shows and displays on the riding school premises in present day Martiteva Street, and the area of the Burza served as the fair grounds. The period between the two wars saw this area developing into a distinguished quarter of Zagreb. Here were the buildings of the former Stock Exchange in 1925-1926 (at 3 Burza Square), the most significant work of the architect Kovacic, the round-shaped Exhibition Pavilion created by Ivan Mestrovic (today's Croatian History Museum) and the Djuro Salaj Hall which were all built at approximately the same time as the three nearby squares: Burza, Great Croats and Petar Kresimir IV Squares, in accordance with the zoning plan of the east part of Zagreb.

In the Thirties a new style and concept, called functionalism, appeared in architecture and here the Zagreb School of Architecture promoted it. Building activities were flourishing in those years, as Zagreb was becoming an important industrial and business centre with approximately 280,000 inhabitants before the onset of the Second World War. The suburban settlements were rather neglected and most of them sprang up spontaneously along with the inflow of new population, which was evident in Tresnjevka and Trnje.
Mirija Juric Zagorka (1873-1957)
Josip Juraj Strossmayer (1815-1905)
National and University Library