The central part of the country is a slightly higher plateau which covers part of Hainaut, of Brabant, of Namur (Namen), and borders on Liége (Luik). There the land is undulating, the soil is rich, the climate milder than in the rest of the country. A great number of wide valleys appear, and to the north of this region one finds the last impressive remnants of the expansive Coal Forest which was a dividing line between the Franks and the Celts at the beginning of the Christian era. Toward the west of the central part is located the Hesbaye region, an accentuated, fertile terrain consisting of a crevassed plateau covered with a thick layer of clay soil.
The southern part of Belgium is a comparatively high plateau; it begins at some 600 feet on the right bank of the Meuse (Maas), and rises to about 2,100 feet at the plateau of Botrange. In this section there are regions of marked individuality, like the Condroz, the Famenne, the Ardennes, and Belgian Lorraine. These very picturesque parts are among the oldest settled regions of Europe; in the many grottoes and caves, relics of prehistoric habitation are to be found. A great number of streams cut deeply through the limestone rocks and rush through subterranean labyrinths. Woodlands are best preserved in the Famenne and on the Ardennes plateau.
The romantic though humane beauty of the landscape, together with its relative isolation, have made the Ardennes region the summer playground of Belgium. To the south, Belgian Lorraine comprises the tip of Luxemburg Province and its capital, Arlon (Aarlen). It is a country of weathered rocks and weird hills.
As a whole, Belgium's physical aspect presents no extremes. The lines of its horizon are calm, the slopes of its hills soft, the terrain depressions spread out gently. It achieves really romantic beauty, almost frightening, in the underground grottoes of Han and in its subterranean lakes. Never is there anything excessive in the proportions of the scenery. Nowhere does nature offer insurmountable obstacles to man.
At the beginning of the Christian era, Belgium was inhabited for the most part by Celts who, like nearly all peoples in Europe, had come from beyond the Rhine. The Celts, who were organized in small, warlike tribes--the Menapians, the Eburons, the Nervii, the Aduatici, and others--were once a challenge for Caesar, but rapidly became Romanized. For two centuries they suffered Germanic infiltrations into their territory until finally, in the third and fourth centuries, the avalanche of Salian Franks covered the northern part of the country and was stopped only by the great Coal Forest, a rampart of wood, which did not appeal to the agricultural invaders, and which, furthermore, was organized as a Roman frontier zone. For fourteen hundred years, the two ethnic groups inhabiting Belgium today, the Romanized Celtic Walloons and the Germanic Flemings, have lived in the territory they occupied at the end of the fifth century. The language frontier has remained practically unchanged, and if the French language gained influence in Flemish territory it happened not through frontier contacts but through administrative channels and for reasons of social prestige.