Germans Take Brussels — Start for France 115 Finally, across two-thirds of the gap between Lille and Maubeuge runs the Scheldt River, a sort of moat, in front of the Maubeuge-Lille line. For the German army at Brussels and intending to invade France the gaps between Maubeuge and Lille and between Maubeuge and Namur were prac- tically the only possible roads. To go to the west beyond Lille would mean to extend an open flank to the Anglo-French forces from Namur to Lille, while the narrower stretch of land between Lille and the sea is flanked again by the first class fortress of Dun- kirk. Such a detour would also be far off the main railway lines. To go east of Namur beyond the Meuse was equally difficult and unattractive to an army whose time was limited, because the Meuse route was closed by a series of fortified towns in France, notably Mezieres and Givet. One more detail, Charleroi is on the Sambre about half way between Namur and Maubeuge. The river runs from southwest to northeast and a French force lying behind it would have its flanks covered by these fortresses. Similarly Mons lies between Lille and Maubeuge, both squarely on the German road to Paris. It was plain from the outset then that once the German army had occupied Brussels, wheeled left for France and begun its advance, spreading out east and west as it moved, the first considerable encounter would take place about these two towns of Charleroi and Mons. The Germans were at Brussels on August 20.