The boulevards of Brussels encompass two geographically separate series of thoroughfares. The inner boulevards (boulevards du centre/centralelanen) include boulevards Adolphe Max, Jules Anspach, Maurice Lemmonier, and Émile Jacqmain. They were laid out between 1867 and 1874, following the decision to canalize and vault over the Senne River. The boulevards bisect the lower town running from the Gare du Midi to the Gare du Nord and were designed by Léon Suys. The new boulevards fostered much urban development with construction of many upscale commercial and residential buildings.
The outer boulevards (boulevards extérieurs/ringlanen) known as the inner ring or little ring (petite ceinture/kleine ceintuur), were constructed between 1818 and 1840 following the line formed by the circuit of the second town wall, which was ordered demolished by Emperor Napoléon Bonaparte. The imperial government decreed roads to be built but work was sporadic and came completely to a halt in 1815. In 1818, construction recommenced following plans drafted by Jean Vifquain. After Vifquain's death in 1833, the northern and eastern boulevards were completed, lined with trees, and bordered by a high grill to facilitate collection of tolls on goods entering the city. The boulevard de l' Abattoir was the last to be laid out in 1840. The term "boulevard" is used to designate the thoroughfares that trace the ramparts. The appellation "avenue" is given to label the highways paralleling the boulevards.
In addition there was a range of highways designated boulevards, avenues, and roads built beyond the ring roads in the 19th and 20th centuries in conjunction with suburban development of the metropolitan area.
Historical Dictionary of Brussels. Paul F. State.