The armies along the Danube will soon command our attention.  As they follow the river toward Belgrade, the capital of Serbia, it is no longer the “Blue Danube” of the famous German song.  Here, in fact, it is a broad, mud-colored river, dotted with a number of low islands along its center.  Belgrade, where the first shots of the war were fired, is located on rather high ground, backed by a semicircle of low hills in its rear.  But opposite all is flat and, in places, marshy.  Modern guns could, of course, keep up an effective fire across the river at this point, as in fact they did before the actual invasion of Serbia began, but the conditions for a crossing are not favorable.  It was from the west, from the Bosnian side, that the actual attack was made.

Just below Belgrade the river Save, shallower and narrower, empties into the Danube, forming the frontier westward, past Shabatz, to Ratcha, where the Drina, flowing down from the Macedonian highlands northward, joins it, forming the western frontier between Bosnia and Serbia.

The Drina, where much fighting occurs, is no ordinary waterway, no mere mountain stream, though it lies in a mountainous country.  Before reaching its junction with the Save it is fed by many important tributaries.  Ever swift, often torrential, it has washed out a bed of imposing width, and by a constant cutting out of new courses has created a series of deltas.  It was one of the largest of these islands, that of Kuriachista, between Losnitza and Leschnitza, that the Austrians chose as a base for their first invasion.  From this point up and around to Shabatz lies the bloody field of the Austro-Serbian battles.

A description of this section, in brief at least, is necessary to an understanding of the three Austrian invasions made here, and all three of which failed disastrously.  North and west of Shabatz lies the great plain of Matchva, bounded on its east and north by the Save and by the Drina on the west.  It is a rich, fertile land, but much broken up by woodland.  To the southeast a rolling valley is divided by the River Dobrava, while due south the Tzer Mountains rise like a camel’s back out of the plain and stretch right across from the Drina to the Dobrava.  The southern slopes of Tzer are less abrupt than those on the north and descend gradually into the Leschnitza Valley, out of which rise the lesser heights of the Iverak Mountains.  Both these ranges are largely covered by prune orchards, intersected with some sparse timber.

This is a region of natural fortifications.  Descending southward again, the foothills of Iverak are lost in a chain of summits, which flank the right bank of the Jadar River, that tributary of the Drina River from which the first big battle takes its name.

From the left bank of the Jadar, from its junction with the Drina to Jarebitze, a great rolling level stretches south until the high Guchevo Mountains, stretching in southeasterly direction, rise abruptly and hide the Bosnian hills from view.  From there, southward, the country is extremely mountainous, even the highways being blasted out of the sides of the precipitous mountains along the innumerable ravines through which run watercourses which, though almost dry in summer, burst into torrential streams after the snows begin to melt in the higher altitudes.