At the same time, the cities in Croatia got an important urban makeover. But for size and importance, the urban regulation of "Downtown Zagreb" (largely the work of "Milan Lenuzzio", 1860–1880) was revolutionary. Between Zagreb's longest street – Ilica, and new railway the new geometrical city was built with large public and social buildings like neo-renaissance building of Croatian Academy of Sciences and Arts (HAZU - learned society promoting language, culture, and science from its first conception in 1836; the juxtaposition of the words typically seen in English as "Arts and Sciences" is deliberate, F. Scmidt, 1884), neo-baroque Croatian National Theatre (HNK, H. Helmer and F. Fellner, 1895), and to that date very modern Art Pavilion (1898) with montage construction of steel and glass – Croatian "Crystal Palace", and finally the masterpiece of Art Nouveau – "The National Library" (Lubinski, finished in 1912). This urban plan is bounded by series of parks and parkways decorated with numerous fountains, sculptures, avenues and gardens (known as "Green Horseshoe") making Zagreb one of the first cities built according to new European art theory of "city as a work of art".