As these three army groups cleared out the Wehrmacht west of the Rhine, Eisenhower began to rethink his plans for the final drive across the Rhine and into the heart of Germany. Originally, Eisenhower had planned to draw all his forces up to the west bank of the Rhine, using the river as a natural barrier to help cover the inactive sections of his line. The main thrust beyond the river was to be made in the north by Montgomery's 21 Army Group, elements of which were to proceed east to a juncture with the U.S. 1st Army as it made a secondary advance northeast from below the Ruhr River.