They were constructed following the covering of the river Senne (1867–1871), as part of the major urban works by the architect Léon Suys under the tenure of the city's then-mayor, Jules Anspach.
The covering of the Senne and the completion of the Central Boulevards allowed the construction of the modern buildings that are focal to downtown Brussels today.
[11][12] The covering of the Senne brought boulevards to the heart of Brussels, whereas they had hitherto been limited to the Small Ring, a series of roadways built on the site of the 14th-century walls bounding the historic city centre.
The central boulevards' completion also allowed urban renewal and the construction along them of the modern buildings of Haussmann-esque style, which are characteristic of downtown Brussels today.
[14] In order to accomplish this revitalisation and attract investment, public buildings were constructed as part of Léon Suys' massive programme of beautification of the city centre,[15][16][17] including the Brussels Stock Exchange (1868–1873).
Great freedom was given to the architects; no unity of style was sought nor imposed (other than a minimum height of 15 metres (49 ft) to avoid speculation) and the monumental composition adopted a de facto eclectic approach throughout the immense perspective of the boulevards.
[24][25][26] The first prize of 20,000 Belgian francs for the 1872–1876 competition was awarded to the architect Henri Beyaert who designed the Maison des Chats or Hier is't in den kater en de kat (loosely, "House of Cats") on the Boulevard du Nord.
[citation needed] The covering of the Senne and the construction of the Central Boulevards have left deep traces in Brussels' historic centre.
Following these events, the city's then-mayor, Freddy Thielemans, decided to make the boulevard car-free every Sunday afternoon for the entire summer.
[29] His successor, Yvan Mayeur, wished to expand the Boulevard Anspach into a permanent pedestrian zone with a new street cover, equipped with fountains, works of art, benches and trees.
The area, covering 50 hectares (120 acres), includes much of the historic centre within the Small Ring, such as the Grand-Place/Grote Markt, the Place de Brouckère and the Boulevard Anspach.
[33][34][35] In 1919, the city council ordered the boulevard to be renamed in honour of the alderman and patriot Maurice Lemonnier (1860–1930), who returned from a long captivity as a prisoner in Germany during World War I.
13 (currently the Haute École Francisco Ferrer [fr]) on the Place Anneessens,[35] as well as the old Castellani rotunda (now transformed into a parking lot).